Hello, I'm new to AM5 and these forums and am offering to run a game at this convention. I don't know very much yet about how you all are structuring this convention/gathering or what kind of response you're expecting so I figured I'd toss out a small resume so you have some idea if I'll fit in.
I am a veteran gamer of over 30 years in a variety of game systems, who ran an Ars Magica saga in the 90s that spanned 2nd-4th edition. Redcap still has a link to a partial writeup of that campaign, a friend of mine keeps the link live flick.com/games/RPGs/ars/amnis/
I've also GM'd at a fair number of RPGA conventions (back in the Living Greyhawk days) and have done playtesting with friends for a wide variety of game systems run in convention environments not associated with RPGA-style gaming. I've not yet played AM5, but have crunched the game system against the prior systems, converting characters and ideas that I never got to do when the old campaign ended, and sparking a lot of new ideas.
I have a pretty solid story idea that would lend itself to a convention setting (tabletop pickup game, 4-8 hours long, adjustable to fit the timeline and quite flexible to match the tastes of whomever shows up and in a flavor of Mystic Europe that pretty closely matches the public canon for easy familiarity). I'd prefer people bring their own characters as long as they're about the right hermetic age, but I'll have four pregens (some of whom would be NPC's, some dead in backstory if enough characters are brought) just in case. 3 players minimum, preferably 4, up to 6 could probably be managed. I'd expect the players to be doing magi, but the right kind of companion or even grog could work out ok, especially in a larger group. I'll also have some stock grog NPC's and a companion with social skills that can be passed out where it makes sense that Magi wouldn't go without some physical muscle or at least minimal ability to cope with mundanes. I could probably rewrite the concept it to bring the players down to a typical troup size (1 mage, a companion, 2 grogs, run by 1-3 players) if turnout is expected to be low. (at the moment, the story is just a sketch, although most of the characters and some of the situations are pretty far along, mostly due to my earlier fooling about with the new AM5 game system)
The story is designed to branch, and lets the players pick a solution from multiple options and approaches that fits their talents to the problem. It'll have some elements of social, mystery and combat, but the exact mix varies tremendously based on the player choices and preferences. My experience with Ars is that magi are extremely flexible and will find their own way to solutions, and a lot of the fun is letting them surprise you and rolling with it.
Anyway, if you're interested in having me, I'd be happy to send more details about myself or the story. I'd like to know a lot more about how the con works (would I be expected to run multiple sessions, will there be time for me to play in somebody else's game, how much time do I have to work with, etc).