I mean I don't want to use a computer to emulate the arcade. I want to build a cabinet with the screen, the joystick and buttons, the sound system and speakers, the power supply, the game program on big electronic board, and I don't know what else I may need because the only sites I can find only tell me how to do it the computer emulation way.
The reason why you only find DIYs for MAME cabinets is because if you wanted an arcade machine you can just
buy one. Maybe I'm missing something, but this seems really really obvious to me.
Actual arcade machines are usually much simpler than MAME machines since virtually everything is build onto the PCBs. An arcade machine is just a power supply, some joysticks, and a monitor fitted into a moldy, rotted-out, rat's nest with a few deadly spiders thrown in. If you live in the US you can find arcade machines for sale cheap in almost every city.
If you want something a little more permanent, you should buy one of the fiberglass models from Japan like a NeoCady, or Sega Astro/Blast City, or whatever. They usually have much bigger monitors that you can rotate if you feel like going from fighters to shooters. My friend bought his Astro City on eBay for about $300. It was in California, and cost another $300 to ship it to Michigan via yellow freight. The cheaper route would be to buy an unwanted MVS, or Street Fighter machine or something, but chances are you'll end up replacing everything in it at a greater cost further down the road. The most expensive part is the monitor.