I can't help but wonder if Xbox will ever release their own version of the platform beat em up. The biggest issue I would see with this is how they would be able to produce a game that is similar enough to the concept but not flat out copy and paste.
I am also curious to see who you would like to see featured in a game were this to come true. Master Chief? Castle Crashers? Red Ring of Death?
Exclusives would be an easy choice but, just like Big Daddy was featured in Playstation All Stars, Xbox could have the "first dibs" on certain franchises. Xbox always receives DLC and updates from Call of Duty games... so perhaps a Richtofen could bring his psychotic tactics to the fray? Could Steve from Minecraft bring forth the creepers of destruction?!