@magzilla This may be a bit late since your original post was in April, but I thought others might be interested as well.

Over on the MiSTer FPGA forums there's been a lot of interest in this display:

https://nl.aliexpress.com/item/1005001689746001.html

It's a 9.7" iPad-ish display that can run at up to 2048x1536(but supports lower modes as well). I bought one and it's extremely good value for money, although you do need to purchase some extras (a better stand, a better video cable are probably musts).

Comes in three slightly different configuration - I got the miniHDMI/USB C version. Very happy with it. So far I've tried it with a MiSTerFPGA, a TheC64 and a Raspberry Pi 4 (running Raspberry Pi OS but I see no reason it wouldn't work with RetroPie)

Here it is running on my MiSTer:

alt text

Full thread over on the MiSTer forums: https://misterfpga.org/viewtopic.php?t=3373