I’ve seen camera mounts for motorcycles on the front by the steering but here’s a really radical DIY that shows you how to make a “rear” camera mount for a motorcycle that will fit on your rear peg, where normally a passenger would put his/her foot down.
This mount should support most digital cameras and small camcorders. You have the flexibility to position the camera either front or rear-wards. (or even install two at once!)
Be sure to put a small piece of tape over the mic on your camera or the wind noise will overpower it. (I forgot the tape in my test run video)