I originally tried to contact Sportsman Flyer about the hub they use but my e-mail didn't go through or something so I started searching this forum with keywords like hub, sprocket, etc. and finally found someones post mention moped hubs laced into their wheels, did some more searching here, ebay, and other places, found a complete moped rear wheel with no brakes for $99.00 and was about to buy it when I found 1977 mopeds. The price almost seemed too good to be true but I went head and ordered it, it showed up a few day later better than I expected. Moped parts in general are a great resource for us considering we are basically building cool lookin mopeds.
It is readily available brand new here...
Motobecane Rear Wheel Hub for $45.00 in Brake Hubs from 1977 Mopeds