Looks like the External Lights thread has morphed, so I thought I'd relabel it. I'm thinking of maybe getting a model from
http://www.rearviewsafety.com/products.html at some distant point down the road. I've seen good reviews of their products. Generally, the reviews I've read say hard-wired is the only way to go, and this company makes a quick-connect unit for back-bumper TV installation. As long as I'm travelling with my wife, though, she's my back up camera. It would be nice to have an electronic "rear view mirror" while driving, though.