Air's Ghostly Form is CrAu 5 and creates a fog or heavy mist, which might well allow you to spot invisibles.
Auram Guy was intended to be topped, and designed in under 10 mins.
He was also intended to illustrate the problems with the original question. 
As for Rego-based assasins, I assure there are further tricks in Projects 
Nice!! Looking forward to it.
I believe the ultimate munchkin character at gauntlet to have
the three PeVi spells for magic, fairies, and infernal, level 10 mastery 4 each (= 5-fold casting) [no need to smite angels]
another PeVi parma dropping spell (based on MoH, Concientia's knife)
some spell to blast mundanes (sleep or PeIg), or whatever, killing mundanes is easy anyway, mastered for multicasting
other useful non-attack magic for the rest of the xp (disguise, traveling, social etc)
affinities are a waste of xp, since you can take strong parens + gild trained (GotF) = 150xp + 30 lvls of spells instead (affinities become useful at higher levels)
flawless magic (for all the mastery)
mastered spells
life boost - for those monsters that need some extra penetration (getting fatigued doesn't matter, because high level monsters don't run around in groups)
intellego magic is not needed if you play a Pralician (free major virtue, because ex Misc), but you also get the useless hedgie focus
as for the auram guy: if he was a Craft magus, he could quickly produce those lightning bolts as charged items with an even scarier penetration.
An excellent munchkin, though I forsee a weakness against Hermetic Magi: the Parma dropper needs to penetrate, so does the Call to Slumber.
Not a major weakeness though.
Charged items have better penetration than I feel they should have, and like several other of the Ex Misc traditions in Societates the Rusticani are just so off I'm forced to consider them poorly done.
Apologies to those whose work it was, but some of those traditions are just too good or too bad. In general I prefer the latter.
EDIT: Sorry, I forgot
Affinities are used above because that'll allow you to ignore that officious SG who insists that you stay within the Art cap on p. 32, treating it as a hard cap rather than the suggestion it clearly it. 
Ladyphoenix made a Criamon on the path of Strife that scared the undead out of me. This monster maga was doing some ungodly +20 attacks (I think it was at +27 or something terrifying) and had the parma dropping spell and could chomp a demon under might of 30 in like one or two rounds. When I saw the sheet I shuddered in fear of being the ST.
I lack most skills in munchkinism, but I am in awe of number crunchers! 
I'm not sure how successfully munchkin it really is, and it's definitely designed for general utility rather than killing things, but I've had the following idea for a Spontaneous spell specialist kicking around in the back of my mind for a while:
That gives you Artes Liberales and Philosophaie scores of 5 +2 each, with specialisations in ceremonial casting for additional +1s', a Stamina of +5, each Technique at 5 and a few Forms at 5, meaning you're casting ceremonial spontaneous magic as a casting score of +26 (+2 for loud words and gestures) before roll, aura and Life Linked Magic, for any Technique/Form combination. You can therefore reasonably reliably get a level 15 spell in any Te/Fo combination.
The Cautious with Artes Liberales virtue by a strict reading of the rules I think means that you can do this without any botch dice under standard circumstances (although I'd understand an SG who didn't like that interpretation). This means you can add Life Linked Spontaneous Magic to the combination with less risk of accidentally killing yourself. At unconciousness level, that's enough to cast level 35 spells in any Te/Fo combination. Level 50 could be reached if you're willing to take a heavy wound - there's no die to the damage, so no risk of killing yourself. At least, directly.
I'm sure it's possible to optimize it a bit more than I have done. If I were actually to play this character, I'd probably give them some fairly crippling flaws when trying to cast magic without ceremony.
Get performance magic: mystical corepgraphy for an added +3 to your total.
Really nice number crunching, btw. Slow-ish and powerful.
Xavi
It's not just the SG...rules interpretations like that ought to be discussed with the troupe in general.
Or am I the only one who does this?
-Ben.
That's easy enough-- the Major Flaw: Necessary Condition (ceremonial casting) would pretty much lock you into that form of casting all the time.
-Ben.
As soon as there isn't a single SG (basically a GM), but actual troupe style play, this would be obviously necessary to me.
Now Salutor, I salute you - that is a beautiful munchkinism!
We have player at the table who tries ths approach but I don't believe he's even been this succesful at it!
We have a SG for adventure time, but for cpouncil meetings and downtime play we don't, so everything is talked and consensuated. We sometimes flout common sense if something is so `preposterous we want to see it happen :mrgreen: , but generally it is fairly easy to get a consensus.
Xavi
Thank-you.
Yes, substitute "troupe" for SG where appropriate. I'm aware it's a use of Cautious with Artes Liberales that probably wasn't fully intended, but, well, this is a thread for hideous munchkinism, so I feel less guilty about it than I normally would.
Necessary Condition: Ceremonial Casting certainly works to restrict the character, although it is extremely harsh - considerably more so than the canonical example of spinning around three times (and the flaw does specify the required action should be something fairly simple). I'd probably try to argue for a major version of Deleterious Circumstances instead, similar to the Environmental Magic Condition flaw on page 48 of RoP:M (which halves casting totals when, for example, inside).
Mystery Cults seem like a good opportunity for munchkinism. So, I'll give it a go.
First, when making up the covenant ensure that it there is a Boon to represent an accessible regio where time advances quickly (say, one season in the regio per day outside the regio). A true munchkin wouldn't forget about the covenant statistics!
Then, make up a Tremere character with an Affinity with the Ability Mystery Cult Lore: Cult of the Munchkin (and has the free Minor Focus: Certamen).
The character has a Presence Score of +3.
Spend 120 XP on Mystery Cult Lore: Cult of the Munchkin specialised in "Initiation". With the Affinity, this gives an Ability Score of 8 (initiation).
This means that the character can generate an Initiation Total of Pre (+3) + Cult Lore (8) + speciality (1) = 12.
The Cult of the Munchkin has a single Initiation Script called Re-Focus (see below).
The idea is that the character can change his Minor Focus whenever he likes by using the Re-Focus initiation script. So, effectively, he has a Minor Focus in "whatever is convenient at the time". It normally takes a season to do the initiation, but this is by-passed by stepping into the regio with rapid time-advancement.
Total Cost: 1 covenant boon, 1 minor Virtue, 1 "free" house minor Virtue, 6 Characteristic Points, 120 XP.
This script gives the character a Minor Magical Focus. The field of the Minor Magical Focus is determined when the script is used.
The character must already have a Minor Magical Focus to use the script. The script inflicts the ordeal of destroying the character's original Minor Magical Focus.
The script has a required Initiation Total of 15 (as it initiates a Minor Virtue the Mystagogue knows).
The script has a Script Bonus of +3 (as it inflicts an ordeal of removing a Minor Virtue).
Therefore the effective Initiation Total required is 15-3 = 12, which the character has.
I do not find this character to be specially dangerous. Basically because the auram guy would pass 99% of the filters of most troupes, while the tremere unfocused guy would not. As such I give you a B for your munchkin character. Not bad, but can be improved. 
Still, the advancement regio (90 advancement seasons in a real world season) is true munchkinism to the core. Kudos for that 
THe cult of the munchkin made my morning something funnier. :mrgreen: I have to say that when I saw the regio I thought you were going for a summoning character. Too much CatC and SR#9 lately, I guess.
Xavi
I think the ReMe munchkin is more brutal. He can charm the lightning munchkin to shoot anyone. Can charm the librarian to give some extra books. Etc. Able to ruin every plot.
He must know some effects which destory magic traces.
Another idea:
A maga with presence of 5, Venus' Blessing with some guile and flexibility. She doesn't need to know much magic. 
Ah yes, thanks for the reminder
)I like Xavi's mentem munchkin idea. I'd use deft mentem though (saves other virtue slots), and maybe add a backup against animals.
Only if it also means aging one season in that time... 
Now, i´m just wondering if you had the most perfectly placed typo possible or if it was intentional...
:mrgreen:
Ah, but this is munchkinism. So aging only matters if the saga lasts long enough for the character to die of old age.
If the saga only lasts for a decade or two of game-time then advancing your character an additional 20 odd years (or even 40 or 60 years) doesn't matter. It means you get to play an arch-magus when those who don't access/use the regio are still playing freshly gauntleted magi!
Shapeshifter
I've made a design a while ago using much the same approach as Salutor, with focus being more on spontaneous magic than ceremonial magic, but using some of the same principles. The design is not particularly Munchkin but has some ideas that works pretty well, so I'll share it anyway. The reason for the design was a challenge from another player to use some of the most crippling Hermetic Flaws, and still make a powerful character - thus there is some Munchkinism required to do that 
Virtues
Diedne Magic (Instead of Life Linked Spontaneous Magic)
Great Stamina x2
Cyclic Magic: Daytime (replaces Mystical Choreography)
Enduring Magic
Special Circumstances: Touching the target
Puissant Muto
Affinity with Muto (or Skilled Parens)
Ex-Misc.: Major = Shapechanger*
Ex-Misc.: Minor = Minor Magical Focus: Self-Transformation
Flaws
Short-ranged Magic
Loose Magic
Weak Magic
Poor Formulaic Magic.
Cyclic Magic: Nighttime
Dark Secret
Major Story Flaw
Shapechanger - Ex-Miscellanea
*Since she had a very weak penetration and could not cast spells with range greater than Touch, I decided to have her focus on personal buff spells. I designed a 'Hamskifter' (Shapechanger) Ex-Miscellanea variant based on Scandinavian traditions of Shapeshifting, and gave her a focus within Self-Transformation. The Major virtue Shapechanger was discussed in here in a previous thread, and is not Munchkin in any way. This is just the version I felt good about, but some people in here find it weak for a Major Supernatural virtue and I could easily have pushed my SG further with this. Summed up it is a package of: Unbound Tongue (Mystery Cults), Inoffensive to Animals and a rule on Characteristics when Shapechanging: When adopting another shape and comparing the human vs. the new shape’s characteristics (as per Mystery Cults p23: Statistics of Shapechangers – retain the human score, if higher. This tends to give her animal forms higher Communication and Presence, while Big creatures remain a fair Dexterity and Small creatures retain some Strength.
Comments
She has spent some xp on Artes Liberales (Ceremonial Magic) and Philosophiae (Ceremonial Magic), and a great deal in Parma. On the other hand, she has saved up a lot of xp from neglecting Penetration, and skipping one or more Weapon skills. Instead she focuses on Brawling in animal form if combat is neccessary. When sponting the idea is to double through both the focus and the Diedne Magic, so as to reach high totals. Her arts are spread out pretty well, with an obvious ephasis on Muto, Corpus and Animal however. But scores of 5 come pretty cheap so there aren't many spells under level 15 that she couldn't spont (even with requisites), making her spellcasting very versatile. Her Formulaic spells are focused on spells of pretty high level, that she would'nt be able to spont until she recieves a great deal of xp through play. Also she has a Ritual healing spell in her Grimoire.
Equipment
She wears a long padded Fransiscan-style robe, that is sewn together from parts of various animal skins, hides, feathers etc. While this doesn't do much for her in relation to mundane activities, it gives her the requisites required for changing into a large range of animals including different types of birds, reptiles and carnivores. She hopes to be able to enchant this cloak as her Talisman at some point, with attunement options such as; Animal hide +7 turn into appropriate animal; Clothing +4 transform self /+4 protect self / +4 move self; Cloak +5 alter or suppress wearer’s image / +4 transform wearer /+3 flight. Furthermore, she mostly wields items and clothes from Animal (or Corpus) material to avoid further requisites on her Shapechanging spellcasting.
Generalism - XP
Note that although generalism is very rarely mentioned in Munchkinism, it has its uses in this design. Once Muto, Corpus and Animal are high enough for Shapeshifting, adding xp in all of the other Arts increases the spontable repertoire rapidly as a result of the potential to double or triple the Art. Also it makes the Maga much more capable when it comes to requisites, one of the biggest obstacles for Form specialists. In addition to this - generalism has a few advantages that are often overlooked (from my experience anyway): 1) Easy access to Summae since you could study many Arts, and have relatively low scores (hard to find that Auram level 18 book), 2) Easy access to cheap Vis to study from, you should always have some Vis you could use (and you don't need five pawns of that expensive - and for you most precious - Creo Vis, just to recieve 10 xp), 3) Easier to find able teachers of both Arts and Spells, 4) Easy access to lab texts for spells that you would like to learn (often many more options when learning more than one spell in a Season).
Generalism - Freebies
Also generalists often get 'free' protection. First of all, one might have a better shot at fast-casting an appropriate counterspell. Secondly, with a full years dedicated study one could probably up ones low Forms to all reach a score of 6 - giving a +2 Form bonus to pretty much anything from Soak to resisting Magical Lies. Thirdly, with a score of 6 in all Forms, your Magic Resistance is increased for all magical attacks, in a way that is slightly better than if your Parma was actually one point higher. Oh, yeah - and as a small bonus option, you're very hard to predict in Certamen