At last I have collected all of the pieces needed to capture my bike rides from almost any angle (at least until I start breaking them in the field). I now have 3 umbrella holders of which I use parts from all of them to get the job done. I also have a hand held telescoping boom that fits in the umbrella holder clamps perfectly, two ContourRoam cameras with video and still image capability, one point and shoot camera with video and still capability, a tripod made from aluminum tent poles, and assorted mounts and gadgets from Contour and GoPro.
I am deep into the testing phase of this project and it is very exciting even riding solo. Can't wait to find some other riders to join in the fun once I get things sorted out. The main challenge of course is trying to keep the cameras from "seeing" each other during filming.