I made a prototype mounting bracket yesterday and I think I have it figured out. It is attached on my bike with only the 2 mirror mount holes. I did this on purpose because there is nowhere else near on the 06 to pick up for support.
With the lights on, I'm noticing very little flicker of the HID's as I hit bumps and such. I'm not sure that any other bracket could alleviate this as my bracket is very stout and not flexing at all. In comparison, cause this is what I have on hand, the Gaurald brackets have all kinds of flexing going on, and are nowhere near substantial enough.
Any visible light beam movement is now being caused by the motion in the bikes subframe itself. Though I can see a little movement, Its only because I'm looking closely for it. I never felt like any of the movement of the HID was bothersome and annoying. Of course this could be very subjective. I only run up to around 80mph.
I chose to make the bracket out of 1/4" steel and never tried anything thinner, maybe 3/16" will suffice? Even though the material is 1/4", I can still get both mirror mounting screws fully engaged with thread. I will have to investigate the 06 bike to see if there is enough thread available to duplicate a similar design.
This light kit is throwing bright usable light easily 1/2 mile down the road. I had oncoming cars dipping hi beams at around 0.8 miles. I'm quite satisfied with the results of this kit and will be keeping it for sure.