I have a couple "multicades" but nothing running MAME/Emulation. I have a darksoft Multi-CPS2 in a Dynamo cab.I also have a darksoft Multi MVS cart in a dedicated 2 slot neogeo cab, and I have another dynamo with Magic Sword in it until Darksoft releases their Multi CPS1. I do have an Area 51/ Maximum force 2 in 1 thats inside an America's army cab but its at my moms and I dont think she wants to give it back.

I tend to play most of my emulated stuff on my SNES classic or Playstation Mini

When you start getting into the thousands of games on 1 machine you are 100% right. There's also the issue of horizontal and vertical games; games get squished or stretched or have black bars on the sides. My Multi NeoGeo only plays neogeo games, so the controls are perfect for it. Same for the MultiCPS2. I thought about building a dedicated 1 player cab with a 4 way stick and a spinner that would play only vertical 4 way games and Arkanoid. I know Im weird, I really like arkanoid.

I agree but if you limit the games to specific controls that's not an issue. Like Pacman , Pengo, Donkey Kong, Burger Time, Frogger, Dig Dug, Excite Bike; they all use a 4-way restricted stick, you can also add 2 way restricted games like galaga / galaxian and add 2 or 3 fire buttons and they'll all play just like the arcade games.

There are outliers like playing Arkanoid with a trackball instead of a spinner, its functional but not the same thing. I was over on arcadecontrols for 20+ years so I know a lot about both the right and wrong way to do multicades/mame cabs. Unfortunately throwing a shit ton of games on a machine with the wrong controls is the norm, especially on these unlicensed multi-thousand in one machines.

Betelgeuse get a CPS2 motherboard and a Darksoft CPS2 kit www.arcade-projects.com , all you would need to do is put the CPS2 in place of the CPS1 game, and get a CPS2 kick harness. Then you'd have all the CPS2 fighting games (Super SF2, SUper SF2 Turbo, Dark Stalkers, All the Alpha games, all the versus games before MvC2) and all the side scroller beat em ups ( Punisher got ported, Both Dungeons and Dragons games, Alien V Predator, etc) and some good shmups like GigaWing and Mars Matrix

basically all of these:
https://en.wikipedia.org/wiki/CP_System_II

plus the punisher , SF2 Turbo and SF2CE that got ported to CPS2 from CPS1

"CHAMMA"

its the grounds at the end of the harness instead of being grounds like on JAMMA, they use them for the 456 buttons for players 1 and 2; what traditionally is done with "kick harnesses"

Id be interested in this too, I have an "America's Army" cab converted to Area 51/ Maximum force. I also own a Midway's Invasion board but I'd love to have more variety in pew pew games.