At ATEI (Amusement Trade Show) in London last Jan, there was a company showing a really neat multi-game machine, which had everything in ROM including OS, about 20 classic games. It was not MAME at all, and completely legal. This might have been one of these. The price of the machine was about 2000 GBP, about par for a revenue-earning machine.
I'll have another look for it next Wednesday when I'm at this years show.
BTW there are lots of MAME money-earners in some countries (which shall remain nameless).
The machine I saw was definitely running MAME because when you selected the game you wanted to play from the main menu (from a choice of about 20) the MAME startup screen briefly appeared.
What irritated me in particular about the cabinet was that if you were at the main menu and inserted a coin, the coin was not registered. Also if you exited a game to return to the main menu any credits in the machine were lost. This was explained on the machine, however at first I didn't read the instructions and I lost 50p this way. It is these rough edges that lead me to believe that the machine was probably not officially sanctioned by either the ROM copyright holders, or the MAME development team.
It was also outrageously expensive - 50p a go. Why can't retro machines have retro prices?
On the plus side the game selection menu looked very professional although for some bizarre reason the text was in spanish.
Incidentally, I'm also planning to visit the ATEI show next week. I went last year and it was excellent.