CBolt

I want to get new wheels w/ drum brakes for my commuter. The front is readily available, but (how) can I use the shimano drum brake in the rear without using an internal hub? The picture on the shimano website looks like it mounts with a proprietary system, possibly splines and a locknut. Is this correct? I know the Araia drum will thread-on to left side freewheel threads, but its huge. Any other brands I should know about?