I've seen this mount made on other sites. (
here -
here -
here -
here -
here etc...) The only thing that really bothers me about it is the lack of bushings and vibration resistance. Mounting to the bars will direct the triple-tree vibration right to the camera. Everytime I've mounted my cam to the bars, it's been impossible to control the road vibration making the video almost unusable.
I look forward to see how you get by that on your attempt for this design.