I have made a digital camera mount for my handlebar out of a steel bike rack mounting bar and a plastic reflector clamp.And the screw from a broken tripod. It works OK for still pictures on a smooth surface only. I also have taken a few digital movies while riding my bike and holding my camera. This takes care of the shock problem, but the movies still are not very good.
Some problems.
The last two cameras I have owned had the microphone on the front and the wind ruined the sound.
The quality of my $400 digital camera movies is not good enought to really be worth the trouble unless it is very bright outside and there in not much action. Even then it's not very good. I think on a camera at this price and quality level a customer would be unhappy with the best camera holder in the world.
I am on a dial up connection, I can't succesfully email my movies either. (mpeg)