Folding bikes are available with 8, 12, 14, 16 (actually two different 16s), 17, 18, 20 (actually two different 20s), 24, 26 inch and 700c sized wheels.
tcs
Cool. If I ever decide I need one I guess I'd have a lot of test riding to do. I can see how they would be great for camping/cottage type excursions where space is at a premium.