I got the Audiovox mirror/monitor and rear cam set up that used the original factory cam location. It was either $679 or $699 installed (gift, I didn't see the bill.) Installed by Wright's here in Shreveport - super clean install, but the factory mirror couldn't handle the weight. Remove mirror (lose map lights), metal strap mount monitor between the headliner and roof, bingo. And, you gain a little more windshield view area when the mirror moves up next to the roof. Next install I will figure out how to remove the mirror mount wart from the windshield.
Mirror monitor is located exactly where you have always been trained to look when reversing - zero learning curve. You still have a mirror that can be trained on the munchkins in the back seat - angle of the mirror doesn't really hinder your view of the monitor. Have it wired for always on so that the cam is your full-time rear view. Brighter back-up lights are a must with this cam and/or with vaneyes/tinted rear window IMO (big honkin' LED's?).
After the demise of beloved 377, I called Wright's to pull the cam/monitor and XM hookup. Very quick, professional, highly recommended. They will be working on Joe's Dragon once it becomes MY Dragon. Can't wait.

Velvis