I've gone the eBay route and spent 150 bucks to install a mirror that houses a hidden 5 inch monitor. It works with this 30 led color night vision cam. They are not the best quality, although with a bit of work they can be just as good if not better than the expensive products. It's just I found quite a few defects which took time to correct but brought everything up to spec.
The mirror works almost like tinted windows I guess, and has a second video input, on/off, and a built-in reversible switch that makes a world of difference in backing up. The camera from jap sux at night if cars are close behind you, but works great in the day or when there's no immediate headlights on your tail... like backing into a spot for example. I also have a 7 inch monitor connected to my computer, which I might have a second USB video for maybe capturing and/or alternative view angle. I kinda want to mount a second IR camera facing forward, but that's too much of a waste of money for right now.
I had to file a big portion of the moon to get this 30 led to fit in right, so it's a perminant addition to the vehicle. As is the mirror which now uses the stock mirror mount. It all still kind of looks like they belong there, the camera follows the lines of the rear and the mirror isn't too oversized.
There's actually a few choises out there, I believe tone's camera has a much better view angle and picture quality. The one I bought is a bit too big, which just ment more work making it look/fit/work right.

here are some pics: