Lil Bluestem, I know in Austin, Asahi Imports (http://asahi-imports.com/) on 2222 & Burnet sells Texas Sake Kaus, as well as the Texas Sake Company (www.txsake.com). Perhaps ask one of the shops in Dallas to start carrying it too. Its really delicious!
Texas Saké Company
5501 N Lamar Blvd, Austin, TX 78751