So, here's a cool idea.
What if, instead of one GM and many heroes, what if you had one hero and many villian/GMs.
And set it as Megaman, with the GMs being the boss monsters and controlling/designing a level.
Granted, I don't see much actual roleplaying happening, but it could be cool as a "challenge game".
Also, biggest problem is: What do the extra BMPs (Boss Monster Players) do on off levels?
They'd have to contribute somehow....