Very nice, and I like the idea of using a local auto paint shop.

One idea, if you just want to make the one-off bespoke panel, but still support anything bigger than a RasPi cantilevered out the back of it, is to combine your custom panel with an off-the-shelf (ha) rackmount shelf.

You can get shelves that are fairly thin but sturdy sheet steel, that have a lip and clearance below (such as for room for zip ties or non-flush screws from the bottom. And you can also get ones that are flush with the bottom of the unit, and use adhesive (including Velcro pads) to mount the components on top.

If you want an easy way to make a front panel that doesn't look as good as the one in the article, you can get a rackmount gap filler panel, which will probably be thinner steel sheet metal then the aluminum one, and drill/Dremel/lasercut? whatever holes you need in it.

Another option is starting with a rackmount drawer, such as those by some DJs/musicians in road cases. It's a rackmount front panel, plus an all-sides enclosure rest of it. Which you can unlock and slide out. to access the internal components, without unracking. You can drill/cut air holes. Cabling to the rear will vary depending on the design.

This guy might be good at designing but he is really bad at 3D-printing. All of that post-processing would've been completely unnecessary if he'd made better choices about material and print orientation.

Fyi the latest builds of OpenSCAD have a new fast-csg library.

My compiling never takes more then a minute, usually it's less than a second.

Waiting over an hour to compile a CAD drawing seems untenable to me.

https://ochafik.com/jekyll/update/2022/02/09/openscad-fast-c...

Showing OpenSCAD without showing any code, or even really talking about the code is a real shame - there are some cool ideas in here, but none are shown (e.g. "I even made an algorithm to calculate the screw positions evenly").