There are many older threads talking about backup cameras and monitor types and positions in both generations of AVs. You might want to read some of them for ideas but basically in first generation AVs the owners who wanted to upgrade to a backup camera system did one of several options.
1. got a backup monitor mirror (which you already have discussed.)
2. got a small monitor and put it in dash near a center cubby hole by removing the dash cover and then cubby itself replacing it with monitor then replacing dash cover.
3. spent money for aftermarket head unit with camera monitor capability. Some bought flip out screen models but some found they had to shorten the shift lever to avoid the screen from hitting if it came out automatically, other owners had screen set to manual to come out when gear selector was moved. (I know you have voiced displeasure already for this option.)
4. about the only other option I can think of is to get a backup camera system that ties into an aftermarket GPS system and have it mounted to your dash or windshield.
Here is a link for a Garmin camera that is wireless and works with many models of Garmin GPS units:
https://buy.garmin.com/en-US/US/p/501486#overview
The most like a factory look would be like a head unit with a large screen like on a second generation AV that could be in a kit form from a company like www.crutchfield.com and their customer service could help with all wiring harness and adapters to keep steering wheel controls too. I think they even sell dash cover to fit new unit.