What I did, was find an old set of wheels that used a freewheel. Since I don't run freewheels any more, the wheelset was useless to me. I found a flip flop hub whose flanges were the same height as the hub on the donor rear wheel. Took the donor wheel apart with a spoke wrench and rebuilt the wheel with the flip flop hub.

I thought the fact that the freewheel hub used an offset spoke pattern would make the spokes too short on one side, but the new wheel laced up fine, and I put a wheelset that had previously been lying around just taking up space, back into service.