Hmm, I would have to think that the same technology for an input device would be technology similar to a Wiimote, don't get me wrong. However, having a stationary bike with a motion sensor built in somewhere... Just hack the Wiimote, look over the schematics, and see if you can build that into the bike wheel, and/or pedals. It might be worth the shot. I'd probably build some of that i/r technology into the pedals, as opposed to the wheel, obviously...
EDIT: A brilliant plan, just take the Wiimote, or two, and attach them to the pedals using the wriststraps, then tape them onto the pedals, or hook them, whatever, then program around the Wiimotes, and there you have it.
EDIT: A brilliant plan, just take the Wiimote, or two, and attach them to the pedals using the wriststraps, then tape them onto the pedals, or hook them, whatever, then program around the Wiimotes, and there you have it.