Ive currently invested in some reversing cameras, screens and mirrors. Most importantly a px option that looks factory. I have a DVR Mirror with a 3.5" screen. This mirror basically has 2 cameras built in, one on the front side to record where you are driving onto a sd card, also one behind the mirror able to record inside the car, with auto dimming. I also have the option without the DVR which makes it cheaper.
only have to shave a bit off the plastic behind the mirror so you can adjust it properly. i will be looking into heating a reshaping the next ranger i get in to do and this should only need to be done on the DVR type, and this is on an XLT will be doing a DVR on an XL probably next week.