We like the 5" screen Voyager system. Camping World sells it and at least our store has a demo system on the floor to see how the product performs before you buy. We like the 7" screen Voyager even more, but CW does not source that system.
When we got the trailer, we installed a Rear View Safety system that was about $250. We purchased a GoPro suction cup mount and located the camera in the rear window on the inside of the coach. We powered it with a 12 volt
jump start battery, so no wiring was required on the Airstream. The TV screen is a suction cup mount to the windshield and powers off the cigarette lighter socket in the dash. Works great in the day time. Not so good early in the morning if the rear trailer window is covered with condensation or rain drops. At night, we get a bit of glare and our experience is much less satisfactory, but we have been stopping earlier in the day so it has become less of a problem for us.
The AS service departments often run specials on camera installations. Give them a call and see what they can offer.
So you have lots of options. Good luck with your search. Pat