Pretty much I had casually mentioned at work that I was interested in building a MAME cabinet. A co-worker over heard me, and just happened to have one that he was looking to get rid of, as in FREE! So after a long drive and some painful hauling I was in possession of a Wizard of Wor, cocktail styled arcade cabinet.
I had been given an old PC from my girlfriends family, with the help of a specialized boot CD, I had a fresh install of DOS 7 as well as an emulator and front end.
On the hardware side, it was fairly simple to make the conversion from PC to arcade cabinet. The video input to the monitor was simple a VGA connection with composite sync and a slower refresh rate. Twisting the hsync and vsync lines together gave me the composite sync signal, and the software took care of the refresh rate. For the audio, I simply bought some $2 computer speakers at Goodwill (Woooo Goodwill!) and connected the speakers in the cabinet to the driver board inside the speaker enclosure. The keyboard was a bit tricky, I removed the controller board from inside the keyboard, and traced the signals from the necessary keys (up, down, left, right....). I then wired the buttons from the arcade to the corresponding pins on the controller board, and it worked like a charm!
The only problem that I ran into was the fact that the monitor had to be turned on AFTER the computer booted into the front end, otherwise the picture wouldn't sync properly. This caused the screen the rip diagonally, making it pretty much useless. Once I found this out, and by find out I mean I accidentally stumbled upon it, it was smooth sailing.
One feature I'd like to add in the future is the ability for the game to save hi scores, but this would require a newer, non DOS version of the MAME emulator. While this would be nice, I think a whiteboard hung on the wall next to it will have to do for now :P.