I made a bracket from sheet aluminum which went under the Mirror mount on a faired bike (not an FZ).
It was simple and plenty strong. Make a paper pattern, cut to shape, drill your mounting holes, and twist into shape if the mount doesn't accommodate the angle you need.
I used 0.125" sheet aluminum which was overkill, but its what I had. We sprayed it black and it took less than 30" to fab up (longer for the paint to dry).
When / if I get G pro, I'll mount mine there as I don't need my own video capturing Hoon like habits * IF * my Speedo should go beyond the posted limits.