I was also looking for a nice touchscreen/nav setup for the car so that I wouldn't have boredom during my drives, and so that I could get around easily in San Antonio etc.....I already had an aftermarket setup, so I sold that and started my hunt for a headunit that would do everything i need....BT, Nav, connect to the overhead screen, dual zone, HD, Pandora, USB, etc.....and at the same time i wanted a backup camera...
I went against everything Steve told me, and bought a $15 CMOS license plate camera off of Ebay from China.....install was pretty simple...had to remove the tailgate, and I did the clips at the same time....had to run the wiring behind the handle/lock panel without drilling any holes....just added a rubber washer in the screw hole i ran the cables through....
Since I didn't have a headunit, I connected it to the overhead, and I have to say...i can't tell any difference in picture quality between this and my neighbor's Alpine CMOS.....If this things goes for a year, at $15 I'm very happy....great unit and you can't see it mounted on the plate, and you can't see the wiring either....