Rear Vision - anyone tried rear vision camera yet?

[Erax]

As per topic title - just wondering with comments about rear vision and tinting etc - if anyone has tried installing a rear vision camera. I've been looking at some GPS/rear vision camera combinations on ebay. I already have a GPS (keeps telling me to go into people's driveways) and figured maybe a combination might work (apart from all the people breaking into cars to steal GPS units).