That list of characters was just awful. If xbox were going to have they're own SSB style game they would have to use xbox exclusive characters, ones they own the rights to. I wouldn't be surprised if xbox tried to cash in on this as well. Super Meat Boy, Avatar, and Banjo-Kazooie would be a definite no.
With PS3 you have:
Jak and Daxter
Ratchet & Clank
Xbox has a lot of exclusive characters too but none that really move fast enough or could be seen without a gun.