Have been through the same thinking process...

1. I currently have the license frame camera. I actually wished that it was mounted higher to give more of a "bird's eye" view.
2. Although there is a lot of hype about "super" wide angle, I find it more confusing to have the entire parking lot on my screen. A 90 degree angle would just be fine.
3. The more expensive and better cameras are CCD, the cheap ones are CMOS. If it doesn't state what it is, it's likely CMOS.
4. The smalles and best camera I've found is this one:
http://mywebpages.comcast.net/yanlab...ew_camera.html

or here:
http://www.security-cameras-cctv.com...nes-p-704.html

It mounts in a hole of just under an inch and is less than 3 inch long. It doesn't have infra-red illumination, but with my backup lights that's not an issue. Still too big to mount in the brakelight.

There is also a bracket mounted one that could be arranged to tuck under the brake light, or mounted INSIDE to peek through the rear hatch glass for a safe and stealth install:
http://www.security-cameras-cctv.com...nes-p-705.html

or:
http://www.supercircuits.com/index.a...OD&ProdID=5628

6. You can mount the above next to the license plate but it requires drilling through metal. Can also be mounted in the keyhole but there is no wire harness running from the lower doors, so you have to fabricate a water tight, abrasive resistant conduit. Problems with kinking and repeated flexing...

7. This spy-camera could easily be mounted INSIDE the brake light, or glued against the rear hatch glass:
http://www.spysonic.com/Mini-Camera-...s-p-18023.html

Like to hear some thoughts!

Bart