Lump,
The Florida Flywheelers produce 3 swap meet/tractor shows each year. Nov., Jan., and Feb. These also include a very large flea market/swap meet area. Their grounds encompass approximately 240 acres. Not all is swap meet but a great portion is. I have been told that walking up and down each aisle is around 18 miles total. You can't walk it and look at everything in one day...even with a golf cart it's hard.
You can find anything here. Tons of old tools, hit and miss engines, tractors, tractor parts, and much more. Because of the diversity, you get a LOT of people. Shows run 4 days, Wed.-Sat. The good thing is you can set up the Wed. before the show starts. Lets you get out and see what the other guys have before the general public gets in.
The other really good thing is that for all you folks in the North you get to go someplace warm in the winter. We get a lot of folks from the Midwest and Northeast. I would think that a show in Ohio would be successful...providing you held it in the warm weather months.
One reason that I think these shows are such a success is they have something for everyone. Not just the guys.
You can look at their website and get a better idea of the layout.
As was said in the movie Field of Dreams..."If you build it, they will come."
Good luck, Mike