a battalion wars assist trophy would be cool. It would be cool if they set it up like the small mini marios you get to follow you in super paper mario. When you press B your army does one moves and when you press A it does another move. It could be a cool AT. Imagine all those soldiers just following you around shooting, there could be one gunner inf, one bazooka and one plane or tank. I think it would be pretty cool to have those things follow you around, even if it was timelimited.
Speaking of Super Paper Mario, I was looking in my booklet for the game the other day and turns out it has the same creator as brawl. Its just a thought, Hulk that would be a pretty good smash-it-up idea.
Sadly...infantry is just a 2d AT that goes on the screen and hits people. As for Paper Mario...he's already been in Smash It Up of IGN...I just realized it's not really a self-made smash it up if it was already made. I don't know why, I feel like it's violating something...not copyright though...haha