like everyone else said, this is easily done. the coin mechs simply have a switch at the bottom of the shute that is activated by a coin passing through, you simply need to extend long wires from these switches and connect them to the wires attached to two of the buttons in the xarcade unit. i believe by default, the pinball buttons on the ends of the panel act as the coin buttons in mame, so you could just tap into those wires for your coin mechs. you can even still keep the buttons connected if you wish so you can insert coins either by inserting an actual coin, or pushing the button