> Yeah, sure. I will edit the ROM files that change every second version of MAME anyway > even though the emulator's source code could be able to switch off certain screen > elements on the fly, without having to fiddle with actual game data.
It's pretty simple logic actually. If disabling layers won't do what you want to see, the only solution here is either messing with the graphics or the program code from every single game you want it to work. Both involve ROM hacking on a custom version of MAME.
So you don't want to edit ROM files that change every version of MAME, but you want to change every version of MAME for every specific custom change you want to see? Here's what it could be a great discovery to you: Why not stick to a specific MAME version and ROM hack something that no one cares about except you? It involves touching MAME source code to alter the game specific ROM CRC32/SHA1 it asks too.