It's rainy out, which means I'm inside tinkering. I've been thinking about how best to integrate and insulate the Rpi, and found a slim slide-in case for it that actually looked like it might fit inside the Lubitel if I removed some more plastic.
Excellent design by Walter on Thingiverse: https://www.thingiverse.com/thing:604915/remixes
Only change I made was adding a slot for the RPI ribbon cables.
I gave it a test print on my Mars 2 Pro, and a few hours later (plus clipping a TON of supports) I had a very decent-looking case!
A TON of annoying plastic removed later with pliers, and we have an excellent fit!
It doesn't stick out as far as it looks like in the picture above, and I really like how I don't have to worry about shorting now. Since the case is pretty slim, weight hasn't been affected too much either.
I'll flip the orientation from the picture above so that the camera cable slot and IO pins are facing inwards. It will also allow me to epoxy this case in place once I'm ready, as the RPi will slide nicely out of the bottom! There looks like there will even be space to run a right-angle USB cable internally from the RPI to the battery pack, which opens up some hinge options too.
This turned out to be an excellent decision. I still have a lot of work to do, but it's a lot easier when you're not worrying about exposed contacts and shorting. Only downside is I need to find a new button - the case slides exactly where the threaded end sits. Bummer.