There are toolkits out there that will let you peel them apart and see / replace the resources inside. I used this to swap out one ROM for another so I could play the Nintendo NES version of Tetris on my Wii.
Downtown Special: Kunio-kun no Jidaigeki Dayo Zenin Shuugou! http://www.romhacking.net/translations/226/
Romancing SaGa 3 http://www.romhacking.net/translations/416/
Seiken Densetsu 3 http://www.romhacking.net/translations/440/
(Note: None of those links will point you at the ROMs themselves, just translation patches.)
http://www.amazon.com/Namco-Arcade-Party-Cabaret-Cabinet/dp/...
The funny thing is that these titles aren't emulated, per se. They have re-implemented the original hardware (including Z80 core and various sound chips) and distilled it down to an FPGA, playing the code off of the ROMs stored in EEPROMs or Flash memory.
That's only a problem if you feel Namco should be able to continue in the copyright for those works obviously, I'm just pointing out that a difference in intended market isn't sufficient for Namco to drop interest in copyright.
Namco (& Midway in the USA) stopped making these arcade machines 30 years ago. One could easily argue that that is WAY out of production and there's no possible way Namco could be harmed by bootlegging Pac-Man ROMs into a MAME cabinet and placing it into a Chuck-E-Cheese.
But, lo and behold!, Namco is making arcade equipment and selling it again. There's definitely an economic impact now.