> Not completely related but, are there any arcade game titles that had midi music in
> them? As far as I know, midi files were mainly used in PC titles.
> If there are some arcade titles, would Mame benefit from an attached Roland sound
The Keyboardmania games contain a Yamaha MIDI sound module (analogous to a Sound Canvas) which sounds the notes the player actually plays on the keyboard.
Beyond that MIDI was likely the format of origin of most VGM; even stuff played now by orchestras and streamed off HDD/DVD/Blu-ray typically originates as MIDI files. For chiptunes it's usually converted to a more compact and easily-parsed format for in-game, but some games do have real .MID files in their ROMs being played live by the audio CPU.
But in the meantime here's a practical demonstration of MAME playing on a Sound Canvas: