From the Frugal Filmmaker
Suction Cup Camera Mount
As usual the Frugal Filmmaker has exactly what I want. He uses the suction cup system some of the others use, but he uses a ratchet strap for secondary support, or in case the suction cups let loose and you lose your camera. Although he uses this system on the hood, he switches it to the bottom of the windshield for more stability, but the system could be used on any part of the car with some imagination I suppose. He also tries it on the back window for, in my opinion, a much better shot. And moreso, he puts it on the door window so that you can still open and close the door, which makes for a good moving shot. After he says goodbye he still uses the suction cup once more on a mirror with the camera angling down to show him washing dishes, proving this system is not just for cars. He also explains how to use a polarizer to avoid reflections on the windshield.