I put in a pioneer DVD deck with the backup camera and bluetooth. Deck is the AVH-2400bt, you can add a GPS module, HD Radio module, backup camera and sirius or XM. Also controls pandora and ipods through the screen. different pioneer models have more modules included in the unit.
Camera was a "crimestopper" model specifically for installation in the tailgate handle and you can turn the guidelines on/off. As you can see, trailer hookup easy with it.
Deck was $299 from crutchfield with all the harnesses and installation gear, camera was $89 from walmart online.
The kenwoods have a much better price for the GPS equipped units (wish I had seen them first). The pioneers GPS/traffic add on module alone for this deck (AVIC-U250 or U-260) is at least $300, XM radio module (GEX P-90) is about $100 if you shop around. You'll Also need a harness for steering wheel controls. Bluetooth phone works great, always clear.
If you want to install a camera in the tailgate handle it is pretty easy, entire installation took less than an hour. you don't even have to drill in the body to run the wires to the cab, there is a rubber dust cover/grommet at the drivers side rear of the cab that you can run the cables through and access the wiring harness. Only drilling will be in the handle opposite the key opening (after you remove the handle from the tailgate).