The camera looks like a great product, and compares favorably with the $250 optional camera on my van. It also looks like it will be extendable to the wiring on your RV, with 50' of wire to get it to the front storage area on the fifth wheel, then another 20' to get it inside the truck to the receiver. Then it is a matter of buying a replacement camera, and wiring both into the truck, with a easy way to change the wiring position.
I was thinking of getting this 'dash cam' that will record what is happening directly in front and behind my car on a 32 GB SD card.
http://www.aliexpress.com/item/2-7-HD-1080P-Dual-lens-Car-DVR-Rear-view-Camera-Dash-Cam-Recorder-G-Sensor/32259029995.html It will have dual camera's and they do make models with rear view mirror mounted receivers, this model is not one. (keep searching they have them at this website).
It would be fairly easy to keep looking around and find one camera that has RCA jacks (like the one that you are looking at) and buy two of them (they are not that expensive) and use the camera from both packages, then use one camera display for the first 4-5 years, and have the spare if the first ever breaks down.
Put in a search at that website for rear view camera and you get several thousand to pick from. Many have the 4.3" mirror mount that you where looking at from Amazon.com
I put a wireless camera on my motorhome, with the transmitter on the back, and wired to a switch near the drivers seat. I could turn on the receiver, and power the 12 volt camera on the back of the RV, it would give me a small view of what was behind me. Problem was it was a 'reversed image' so that it was looking directly at what was behind me, not a 'mirror image'. So what was on the left of the camera (passenger side) showed up on the left of the display picture (drivers side) while what was on the drivers side was on the right hand side of the display. After getting used to that, at least I could tell if I was going to run something over! and avoid it. The camera was only about $35 and was more intended as a front door camera, or security camera. It did what I wanted it to, for a very low cost.
Happy shopping!
Fred.