A muto vim spell that is enchanted into an item can only be used to target effects that the enchanted item produces.
From this, a twinky sort of thing to do is to enchant wizard's communion into an item to increase the penetration of one of the accompanying effects. I'd like to hear people's reaction to this.
But the most interesting expression of this questionable tactic might be to put the effect into a familiar bond. Thus allowing the the familiar or the magus (one not both) to augment the bond effects that target the other.
So why would you disallow it or why isn't it anything that a SG should worry themselves about?
'Wizard's Communion' wouldn't work on an item or bond if you use its description as written: "This spell lets magi combine their power to cast spells." Nothing else. As this spell does not really fit into Hermetic theory, it would also be hard to find a reason to interpret 'cast spells' as more inclusive than its actual wording implies.
So 'Wizard's Communion' doesn't allow magi or magic items or bonds to modify effects of magic items or bonds. But since - as you already mentioned above - a MuVi effect in an item or bond cannot effect any other thing but another effect of that item or bond, 'Wizard's Communion' in an item or bond could not effect anything. So nobody would put it there in the first place.
Funny, I was reflecting on similar taughts a few days ago. Here are my conclusions:
MuVi magics instilled into magical items can only affect effects that are within the same objects as per MuVi guidelines.
Wizard communion is only a benefit if there are atleast two instances of the spell. Some would use the term participants instead of 'instances of spell' but it doe not change much here.
Now we need to look at how WC works. I say that WC uses the inner power of the participants (Gift) to disdribute the strain of the main spell amongst them thus augmenting the general power of the magic sourrounding the casting of the spell a bit like vis would do.
That beeing said, to transpose the effect to magical objects, you need sources of magic (emulations of the gift) for the WC to work.
Here is how I see it could be done:
Let us take 5 identical magical objects. All of them can cast the same spell. They also have WC invested in them. I submit that the object would combile their power throught WC to cast one spell with an augmented Penetration
Major Magical objects (5)
Lance of Light
1st Effect: Final level 65
DEO 50 (Base effect; +5 50 Times per day, +10 Pen 20 Penetration)
2nd effect: 22
WC 20 (Base effect; +2 6 Times per day)
These lances were all created magically by the great Arch Mage Angus of Flambeau as one great weapon that could be spliced into 5 lances. He gave those lances to his retenue during his eternal war against the Infernal forces that would, eventually, lead him to his final demise.
His retenue spent quite some time learning the activation ritual that allowed them to combine their strenght to vainquish evil. This allowed them to vainquish foes worth of legend telling.
Each of the lances were instilled individually but as if part of the same mundane item. As separate entities, they can slay the average demon in one swift blow but if they are combined, it is said they can slay even the most powerfull of dark lords.
5 lances combination = +40 penetration = 64 penetration total
Unfortunately, since the demise of Angus, we have only found four of the lances. As such, the ability to use the true power of the Lance of Light is lost for the time beeing.
As for allowing it to be instilled into the familiar bond, I do not believe it to be possible since you only have one 'participant'
I suppose that a more "rules safe" way of increasing penetration would be to include four wizard's boost effects in the item (range, duration, target, spell effect assuming that they are all applicable) with environmental triggers to go off with their target effect.
There are questions about items letting loose with multiple effects at the same time. I don't think that this is a real issue but dig up the old "items that multicast" thread on the delphi forums if you want to restart the discussion.
In this case if you invest the an effect that is up to 20 levels lower than your intended effect and have more of your lab total free to put into a penetration bonus.
Instilling wizard's boost into a familiar bond might not be a particularily wise choice because the specificity of wizard's boost limits its usefulness to fairly specific circumstances, yet (IIRC) there is no limit to the number of levels that can be placed in a bond and a wizard's boost that ups duration concnetration animal effects to duration sun animal effects might well be worth it if your bond is stuffed with muto animal effects.
In any case, muto vim spells can be placed in items, would you allow them to be placed in familiar bonds witht he same restrictions?