Hi Robo;
To answer your initial question; I have. We have a set of wheels on our T50 (500+lbs team) with Wheelmaster 40H hubs, Velocity Dyad rims and Wheelsmith SS14 spokes. We have a thousand or so miles on them, and I am very pleased. The hubs are easy to service, and come apart with simple tools. I built up two sets of wheels, one with black hubs and one with silver so my wife could choose which went on the T50. I have also purchased more sets of these hubs for my other bike projects. They roll very freely, are low cost, and are well made. They appear to copy Phil Wood in general design, but with compromises for volume manufacturing.
They are also available in 48H.
Amazon.com : Wheel Master Hub Rr Aly Sf Qr 48X135 9Scas Tdm Sld Bk : Bike Hubs : Sports & Outdoors
Please note that these are 135mm OLD hubs, no threads for a brake on the left side.
I have 2mm of shims on each side to bring it out to 139mm for the 140mm space dropout on the T50.
I used these hubs to convert our T50 from 7 speed Suntour cassette (LBS broke a chain whip trying to remove it...) to 9 speed; when the original Matrix rim developed a circumferential crack.
Regarding "They also informed me that it was actually a 'single speed' wheel, since it had threads on both sides... they were looking at the drum brake threads." The threading for the brake is the same as the threading for the freewheel - and identical to what is used on flip-flop hubs for SS/fixie.
I hope that the bearings were replaced, cups and cones inspected and fresh grease installed in your hub.