I was thinkin, I've seen similar rollers on a "outfeed" table for shop equipment, like table saws and jointers, etc.. Harbor Freight might carry one pretty cheap? All you'd have to do is scavenge the rollers and make a frame that would hold them/the car up, and also make one side moveable so you could change the wheelbase for different cars.. Probably wouldnt be too hard if ya had the parts.. If I get a wild hair I may attempt it.. Would love to hear some other ideas or see some similar projects, if there's any out there!?!