The WOWquilts people retired. People would send in their domestic machine to have it stretched (usually for frame use). Although many people were happy with the results, every once in awhile a machine that was stretched seemed to develop problems. And there was no guarantee as to the results.
My Voyager 17 midarm (on a frame) is a stretched industrial Singer. Hinterberg used to sell these, but they no longer make them. I'm very happy with mine, and you can find them used online.
In most cases, I think it's better to buy a machine made specifically for frame quilting rather than having a favorite machine "stretched".