Fox electric. They are in Dallas and Arlington. I'm in Colleyville. I got a quote for $325 over the phone. They said they have installed many outlets for Tesla owners. That quote included the breaker, Outlet, and 45 feet of 6/3 Nomex wire necessary to go over the top of my garage to the other side. I received a couple of quotes around $800, and from Tesla recommended electricians for over 1000.
I was browsing the Dallas forums on the official Tesla site and found a thread regarding Dallas installations. A few people there recommended Fox.