I bought my screen and camera off eBay and am really happy with it. I have it set up so I can see an object as close as 150mm from my tow bar. Here is the pic of it the screen stuck to my rearview mirror.
And a pic of the camera.
and the links to 2 types the guy sells. This shop is very good and I have bought 4 of the first type from them. For a little extra you can get an infra red camera instead of the standard, just ask before you buy.
http://cgi.ebay.com.au/2-5-TFT-LCD-MONITOR-Waterproof-Car-RearView-Camera_W0QQitemZ290160468218QQihZ019QQcategoryZ32826QQtcZphotoQQcmdZViewItem
http://cgi.ebay.com.au/2-5-TFT-LCD-MONITOR-Waterproof-Car-RearView-Camera_W0QQitemZ290187844978QQihZ019QQcategoryZ14946QQtcZphotoQQcmdZViewItem