Towbin has the dealership, but it no longer has Hummer. They closed that last week.
It is at the old Hummer location, which is on West Sahara at the corner of Lindell (about halfway between Decatur and Jones). Their doors were open today, but not really doing business yet (they said because of computer problems). But they were giving test drives.
They plan to move their Rolls Royce & Bentley dealership to that same location. That's not a very long move; RR-B is now on Jones just south of Sahara. I believe the SmartUSA web site may show that location as the Smart address in error.