Here is my backup camera install. Its a little different than others I've seen.
I bought a Jensen all-in-one head unit on sale from Best Buy for $299
http://www.jensenmobile.com/search/?sku=VM9424BT. It has Nav, Bluetooth, DVD playback with external monitor output, remote control, iPod interface, and backup camera input. Sounds good, but I'm on my second unit...another post on the hassles and install, perhaps.
Anyway, rather than a high mount camera, I decided to put it in the stock location. There is a clear plug in the license holder mold for a camera.
15/16" drill does the trick for an Audiovox camera, made by the same company as Jensen.
Looks stock...
Timer circuit to activate it as rear view camera next...