The 2 thumbs become 2 sticks with 2 butons each.
Trying to imitate the arcade unit.

or the Dreamcast sticks

The only downfall might be that the 360 thumbs are offset, which might feel a bit awkward. It would probably feel more natural with the standard controller (no mods) and using the 2 triggers and 2 shoulder buttons.
This is one of those games where the PS3's stick orientation is better.













