Jack from the forums has successfully installed the tiltBoard controller inside of the Xbox 360 tilt controller. I get asked a lot if this possible. I guess that answer is now yes, though I have not tested it myself. Check it out here.

While your at the forums, be sure to check out Jeff’s install where he installs a switch that allows him to switch the tiltBoard between the left stick, right stick, and off. Check that out here.