Looky what I found, it's a 7 minute long mp3 1970's-1980's arcade ambiance. TRON is to be heard in there somewhere, along with crystal castles somewhere.
Hopefully that won't be considered illegal music downloads.
Here's the site I found it on, it's the site for some 3-D Mame UI, really neat lookin, can't find a download link though.
Definitely check out the arcades section, someone's supposedly working on a remake of Luna City for it.