A couple of days ago I mounted a RV camera on the license plate. It was one of those cheap models, but it really serves the purpose, good overall monitor, wireless transmitter. Overall is just fine. I mounted it on the bottom screws because the trunklid was just barely hitting it. Then I snaked the wires under the plate and thru that hole behind the plate. Because of all the supports though I couldn't get it snaked through to the taillight bay on the right. So I went up and over tucking the wire into the moulding edges, then made a small slit in the rubber seal and snaked it into the car that way.

There is not very much room in there to get at the wires, hanging upside down tring to get your hands in there is painful. I ended up, at least for the time being, buying a very small 12V battery from radio shack fro $34 and connecting the camera to that. We'll see how long that lasts, it's a sealed battery that can be recharged and I didn't have to clip any of the wires in the reverse back up pigtail. But all in all, it works great, great view of the rear and I can see if I'm going to hit something.