The sensor bar is just a strip of IR leds. So no need for hacking there. I just picked up a few from RS and will be building a frame for them around my monitor.
Supposedly, the WIIMote can act essentially like a mouse, so any game that can be mouse controlled should work. I'm not sure about the accelerometer stuff, though I BELIEVE it works like a joystick. Haven't gotten that far yet.
I still kinda like the wiimote solution over the aimtrack just because it's wireless, but, the aimtrack is very compact and easy to fit into just about anything. I guess it'll depend on whether I can get pairing to be a smooth process and how well the tracking works.