Somewhere, there's a DOMA Ruling joke in here...
But seriously folks...
I'm making one right now--it's a tractor seat, with an early Ford axle housing "bell" (half an axle housing, that bolted to the center section), mounted to an early Chevy spoke wheel (the flange of the bell fits the center opening on the Chevy wheel... a Ford wheel was too small and the bell hung over the sides).
I've got it started, but other things are taking priority.
I won't put wheels on the bottom of it, but I think I'm going to figure out a way to make the seat swivel. Shouldn't be too hard to do... An old axle, wheel bearing and axle flange from a different rear end will do the job, if I can't find something else.