Well, the problem I can see is what shop has the tools to align the drum properly to turn. With Drum brakes, it usually uses the big hole to align the drum, the spindle is pretty big, and most times unless the guy that is doing the Job is really attentive, the alignment is Off. Then the cutter has to be small enough to reach in and not have the spindle interfere with the cutter. the drum may be too small.
These days, some Napa do the drum brake turning(Boulder, Lafayette), In Longmont, it is the Mountain Truck shop on Main street, south of 119th.
You may be better off getting a new one, I did last year for a project. Either Cruiser outfitters, or Spector offroad. Do not currently remember.
If neither carry what you need. Check with Cruiser Brothers. They may have what you need.