Just ordered a Garmin GPS that also offers a wireless backup camera. Since my RV already has a wired unit, I was thinking of using mine to put on the rear of my trailer. Hopefully it will give me some additional input when merging or changing lanes. I am always worried about cutting someone off. Here in Ohio, we seem to have our share of drivers that would rather speed up and block people than slow down a little to let someone in.
I know the wired system I have offers the option of a total of three cameras. Rear and usually two side camera. The side cameras can be triggered with the turn signals so to see down the side of the RV.