I found them! It's the Spencers, and there is an interview with them on Ben Harris' website.
As to promoters being performers, on a small scale, it's happening in NYC at Monday Night Magic. Magicians run and promote (and produce) the show. This was also the case years ago with the Magic Townhouse and Mostly Magic in New York (I'm dating myself now). A similar situation also takes place in the party and event business in New York and other large US cities where successful performers are often also agents, booking other variety acts for shows they are doing, and other magicians for events running simultaneously. Many I know make far more booking others than they do in their own fees.
Steve Spill also has a great magic theater show in San Diego called Magicopolis. He both performs and features other magicians in his venue. It's probably the best example off the top of my head. I was also just in Korea doing a tradeshow with my partner Karen, and briefly met a female Korean magician who has her own "magic cafe." We did not get a chance to visit it however, so don't know the exact set-up. She is primarily a stage manipulator, so presumeably it's like a dinner theater.
I don't know how many other magicians she books, but I believe she has a few on the staff.
Any other examples I'm forgetting anyone?