It looks like the 360 version is sold out.
Shame, game is excellent. As a huge MMA fan, I thought this game was much more realistic and more fun than the UFC series. The punches/kicks had weight to them, and the submission system was fun and not completely broken like it is in UFC 2010. Plus, the character creator in the game will just about allow you to make any UFC fighter who's not in the game.
Load times are bad, however.