That would be called a corn crib in this neck fo the woods... although I haven't seen any in model form or kits, it wouldn't be too difficult to build. We have a few in the country surrounding here.
I also have lived in the midwest (Ohio) and these corn cribs are quite common throughout the countryside. They should be fairly simple to build. The structure is open slatted to allow for the ear corn to dry without getting moldy. You jusrt need some pictures and you're off to the races on scratchbuilding.
Good luck
Do you mean a building that looks like this?
http://www.monmouthcountyparks.com/parks/walnford/corn_crib.asp
Dave Nelson