Basically what you would need to do that is the same thing that Dave & Busters uses. All that reader essentially does is checks back with a computer to see how many credits you have, and then credits the machine for you.
I kind of think it would be major expensive overkill for a home Mame cabinet. What would be cheaper is perhaps to get ahold of any card reader, and rig it to insert a credit whenever you swipe ANY card. You could probably rig a bar code scanner to do that too (scan a bar code, get a credit).