How I mounted a 130w solar panel on the roof racks of my 4wd. The panel goes over the top of mounted maxtrax, but still allows your to access them.
The solar panel can be quickly removed so that you can move the panel and tilt it during the day to maximise your solar panel efficiency.
The mount is made out of 32 x 3 flat bar and 8mm round bar.
Just a simple idea, but it seems to work very well!