Google small engines and you'll see more of this sort of thing. I've even seen a miniature Ferrari totally hand made exactly like the original that runs, even with a tranny. When I was a young lad, many years ago, a fella from western Kansas built a very small truck, I believe it was a Sinclair Oil truck that was driveable. Give a man who knows what he's doing along with plenty of metal and a CNC machine and see what he can do.