TX audio stores in Austin or San Antonio?

Ne Plus Ultra
http://www.hometunes.us/

I'm pretty sure you need an appointment for Ne Plus, but you may want to check.

Audio Systems has been around for a very long time, carries (carried??) AR, Prima Luna, other tube integrated lines.
http://www.audiosystems.com/

Whetstone carries Line Magnetic, Leben, and other lines
http://www.whetstoneaudio.com/

The Sound Gallery most likely will not have what you are looking for but a cool place to check out vintage gear
http://soundgalleryaustin.com/

Galen Carol in SA is worth checking out, but you should call him first. His shop is his home (or at least it is a house in a neighborhood, I assume it doubles as his home).

I've been to Galen's house/showroom. You do need an appointment. 

I would go to Rythmik Audio in Austin and listen to their great subs.

Never visited but have had a very good experience buying from Galen.