I uploaded a gallery to Imgur with detailed info, I didn't find any original blueprints, button layout nor WIP photos, but I commented some details on the gallery, and yes, it is almost indestructible

, I made it with live last in mind, maybe a part break but you can replace it easily.
https://imgur.com/gallery/3nnoSSsAs I see your project, here you have a nice problem, the arcade buttons holes can be drilled on any material (steel too) just using a crown drill. They will fit fine and be stable, same for supporting holes and joystick holes. I could say that you have a +-1mm margin of error, the same for a simple wood case. The problem is to include the keyboard switches, that need at max +-0.1mm error. I realized that now by the hard way working on my first keyboard, It is a completely different approach, pieces are smaller and need a fine work, even not allowing a manual/artisan approach (unless you are a master).
Another problem is the tools you have, I have some basic tools as driller, gouges, patience and a circular saw, good for big pieces (you can set a measured fixed width) but not for small ones, when I started working on the keyboard I missed having a flat sanding machine, laser cut/mark, a dremel with a good set of tools, basically more precise tools for work and measure/draw.
I think that if you have a dremel with a cutting disc and a driller, you could try to do your own plate and case, and maybe use the method commented by suicidical_orange, using a laser cut plate, reuse part of another keyboard plate only for the switches and put the two plates together.
Doing the case and plate isn't that difficult (at least compared to a keyboard), also fibreboard is cheap and easy to work with (very heavy too).