If it helps, I can sell you my Thinkware F750 with rear camera. Only thing you'll need is the mounting bracket for the front as mine got hosed in a windshield replacement and no longer sticks.
Personally, I loved it and ran it for the better part of a year, but three annoyances:
1) Every 30 days or so it would gripe about formatting the memory card for data integrity. This would delay startup time from about 5 seconds to until after it repeated that demand, about 30 seconds. Easily fixed by just formatting the card, which is a simple press-and-hold button event.
2) Android app doesn't have live view for the rear camera. That being said, it's easy enough to simply review the rear camera footage to check angle.
3) Rear nighttime quality isn't that great. Having been rear-ended twice, this was the biggest drawback to me, and the reason why I now run two Street Guardians (the V2 one slapped on the front page of Pier28's site). However, in the process, I lost the parking mode functionality as the Street Guardian goes off of USB power and thus doesn't have parking power.
Overall though, very happy with the F750. No video quality problems with the front camera either -- nighttime is superb!
I can throw up some comparison videos between the Street Guardian I'm running now and the F750. I ran them both at the same time for that exact purpose, but haven't had the chance until now to review and splice together the footage. Even caught an ambulance on one of the videos! Street Guardian takes the quality cake, but F750 is feature-packed and takes the feature cake.
I can even throw in a 128GB MicroSD card for you so it will just be plug and play. I have far too many of them anyways from all the dash cams I've been going through. First a Panorama X2, then the F750, now the Street Guardian. Out of three Panorama X2's, one bugged out and the other two killed batteries in two cars on parking mode -- I'm selling those too, but would advise against them if you want parking mode. I'm talking batteries so dead, the LED interior lights never lit!
F750 never had that problem, although I always rigged it up to accesory circuit and ground only so it never knew the difference. I might be able to supply the hardwire kit too, I will check to see if I have it today.
If you're interested, send me a PM and we can work out the details. I'm not in it to make a profit, but that doesn't mean I'll go lower than what's fair
To summarize:
Steeet Guardian V2:
Thinkware F750
Panorama X2: