tnk3291347wrote a review of JVC Adixxion Roll Bar Mount on January 24, 2013
I haven't field tested this yet with my GoPro and Contour, but I put it on my bike (fork and handle bar) and it feels SUPER solid and its much much easier to put on and take off.
At first it doesn't seem like you could pull it tight enough to make it not slip, but it does.
Will try and follow up with a review after some trail riding.
(you do have to have the tripod adapter for your GoPro to use this)