Did exactly that a while ago to salvage the nano texture panel from my 5k iMac. It takes a bit of research to figure out the correct driver board for the specific panel / peripheral combo, but the build process itself was pretty straightforward and it works like a charm.

Can you share any experiences with the driver boards? From what I've seen it looks a bit janky with wires sticking out of the old iMacs chassis and a very old school on screen display. Is the driver board stable? No overheating or signal issues?

I went with the T18 board since it’s passively cooled. IIRC it could also do PD through USB-c, but that would require additional cooling and I just don’t trust noname Chinese manufacturers to do that correctly anyway, so I typically have it hooked up via HDMI. So far it’s been perfectly stable, without any issues. I think there might have been a small addon board to be able to use full brightness as well. There’s a built-in retro display monitoring menu, but I haven’t had a need to use it really, most configurations work from Mac OS, including color profiles and brightness control.

For cables, my iMac had an opening in the back for RAM sticks, which I popped out and wired all cables through. I mounted the driver board on a piece of plexiglass so that most of the ports are accessible directly to the RAM opening. For power, I use a regular third party power brick I had laying around, though some people have reused the iMac’s original power cable with an internal power supply.

Honestly, the hardest parts were identifying the correct driver board and gluing the front glass back on after assembly.