I read in one of the boy magazines (Stuff Magazine I think) that Activision are looking into making a paintball game for the 360.
But what I do know is that on the xbox forums one of the xbox staff that deals with backward compatability was saying that they are in the process of making greg hastings and greg hasting max'd a Backward copatiblity enabled game.
Aparently the reason they have not done this yet was because they were told that a paintball game was going to be out within 5 months of the 360's launch, But now they see that is not the case and They are working on making it a B.C enabled game,
I will keep trying to find the post but as you all know , Xbox forums is not the smallest of forums to search through