ok, so i guess i can just hack open a controller and hook up like the d pad to some of my own buttons, but will XBMC be able to just start playing as soon as i click play or anything, cause i can see what song is playing with my X3LCD. Or do you think its going to be easier to hook up a mini screen in my dash??

LCD's are cool but screens are pimp. Hooking them up is pretty easy. I'd probably add a screen just for pimp factor.
The 5.6" GameCube screens dropped to $100 @ Best Buy around here. The "open box" ones were $80.