Not sure how to make it all work with the TNR but you can get the H-cam with or without monitor at
http://www.trailduty.com/products/hitchcam/hcam.html.
I bought a Hitchcam (and a few other add-ons) from Trailduty. Good prices, fast service and shipping. The cam/monitor setup was hundreds of dollars less than the Hummer dealer and the service was a whole lot more pleasant, too.