masalama - spot on and it is all about #
3 !!
The Turtle and
BritishGuy - Fwiw, I have the following (
purchased in a surf / sports shop inside MoE, down by SkiDubai):
HD HERO2 Motorsports Edition
And coming soon is this:
Wi-Fi BacPac™ + Wi-Fi Remote Combo Kit which will make turning them on / off a straightforward matter (
especially wrt to a cam in the rear window).
You can even take the SD memory card out of your camera, plug it directly into an
iPad Camera Connection Kit , and then view your video immediately on your iPad in full HD.
Ideally you want one cam on the front screen and one on the rear. Now this is admittedly not cheap, but evidence wise it'd be hard to refute, and
priceless for the look on a miscreants face when confronted with damning evidence (
e.g. at roadside and / or in court; preferably after they've perjured themselves 
).