That's awesome, I'd love to find a boardset one day so I can do one of these. Hell, I'd settle for just being able to find a sound board. Awesome work!
Did the ROMs, or MAME itself, ever get fixed to properly play Space Demon?
Reminds me of all the static I got when I tried to educate the emulation community about Taito Operation Wolf, and how it was not correct. The best, really worst, was a half attempt acknowledging the issue and somebody telling them it was wrong.