> I have not looked into this for a long time but I know there are various netplay > builds of MAME now and I wondered if there were any up to date (or not) builds that > supported local networking as the original games did?
Original-machine networking isn't yet possible (core support for emulated drivers accessing the network is coming courtesy of MESS, but it'll also require a pretty decent rework for each driver). Your best option is to use MAMEHub right now.