Crossover Characters?

Video games have had a long history of crossover characters appearing. For the uninitated, that means a character from outside the established universe/setting being available in the game. Examples would be Freddy Krueger in Mortal Kombat, Darth Vader in Soul Calibur, Mike Tyson in EA UFC 2.

Now personally, I'm thinking it is not likely that any such character would appear.

However, if they did, who would be fun?

Lego Star Wars versions?
Mickey Mouse in a Stormtrooper outfit? (This one I could see being an actual possibility...)
Elin Woods with a 9 iron?
John Madden wielding the telestrator of doom?


Edit: Ok... on further thought a Star Wars vs Star Trek game would be perfect..... Not this game, but someone needs to make it....