There's a Midway 18 Wheeler (1979) machine on eBay now, item #360466393526. This actually uses a CPU, but doesn't have a screen. The CPU controls some lamps and rolling artwork. I think it would be pretty awesome to have this running in MAME using the artwork system, but no artwork is available.
The machine's around Savannah, Georgia, and the starting bid is $250. If anyone is interested, I can chip in to purchase it. I can't volunteer to drive to Georgia to pick it up, though.
Apparently, everything's on Youtube now: