Like FreeLanceing, I installed a double-din nav/entertainment system with backup camera capability. The camera is a license plate camera with extra lights when on. It is wired to the backup light on the back of the truck, but I also ran a power cable all the way back to the cab along with the video cable. That is wired into one of the upfitter switches.
With this setup the camera is automatically triggered in reverse, and can also be manually triggered via the upfitter switch. There is a diode (60v/5A) that I put between the truck's backup light and the camera positive to prevent the backup light from being turned on when the upfitter switch is on. I also had to build a 3 1/2 ft. extension cord for when the TC is loaded and the plate is moved to the TC.
This setup works great, and everything is displayed on one in-dash screen so I don't have to have a lot of extra stuff sitting on the dash. I once had someone break my $400 Audi window to get to a $70 GPS unit and didn't want to risk that again!