@phillycheeseman great stuff… Thanks for sharing. I also 3D print many things. I now have qty 4 Prusa MK3S. I try to keep them busy. 
They are fantastic machines. As @chipmc indicated… great minds think alike.
You should check out PolyCase https://www.polycase.com/ for an enclosure. Not only is it a high quality enclosure but fairly economical. Even better all of their 3D models you can download and import right into fusion 360 or you can print them to get a feel on size/shape before you order the permanent one. This even includes a 3D model of their “sub panel” so super easy to design up a backplate. I ended up 3D printing 3-4 different entire cases to find out what one works best before ordering the final one from them. Having the 3D model of their case also allows me to plan out the entire hole pattern for sensors, PB, etc. and even 3D print samples of that. I can modify their 3D model and place holes where I want to mount things, hit print, and then play with where I want the holes. I then found a buddy with a CNC router table. I can take my model to him, made a fixture (3D printed) to hold the polycase enclosure within his CNC table router and he now cuts the holes in the enclosure for me allowing each enclosure to be identical with perfectly cut holes for different external components. Each one takes just a minute to punch all the holes in it.
Also, what I found works really well for the actual PCB mounting is 2-56 threaded inserts. I use these from McMaster Carr. I just use the soldering iron to melt it right into the 3D printed backplate. Then I have nice perfect threads for both the PCB mount as well as the battery slot cover. I found it to be a little easier then self tapping as the self tapping screws. I also use these for my battery compartment as you can see. 
Great stuff… thanks for sharing. Always fun to see how others are doing things.