I just got to try out my new rear view camera today. Its a
Brigade BE-801C camera with BE-870LM 7" monitor and its better than I expected! The picture is crisp and clear and easier to see than the Kenwood head unit screen. It has a built in microphone so you can clearly hear people guiding you back as well as it is heated for winter use and has low light or infrared for night use.
It was really hard to retrofit the cable though. 3 people tried to run down it down the back wall but couldn't. We ended up running it along the roof and into the sloped part of the roof at the cab over.
With cable it retails for about $900. It's a bit steep compared to most but it's a professional industrial grade setup. I'm glad I sprang for it.