TxDOT: http://www.texaschlforum.com/viewtopic. ... ilit=txdot
The Texas Rail Road Commission : http://www.texastribune.org/2011/11/08/ ... earms-ban/
Tx AG : http://www.texastribune.org/2011/11/08/ ... earms-ban/
Texas General Land Office : authorized it back in 2003 when Jerry Patterson took over. I don't think I need a link to prove that one.

Texas Board of Pardons and Paroles : http://www.google.com/url?sa=t&rct=j&q= ... 1.300%2520(Weapons%2520Policy
Texas Medical Board : Maybe? They were looking into it: http://www.texaschlforum.com/viewtopic.php?f=94&t=66894
Are there any others?
ETA: How about the DPS? Governor's Office?
ETA on 16 Oct 15: The following agencies also permit employees with licenses to carry concealed.
Texas Department of Public Safety
http://trailblazersblog.dallasnews.com/ ... -job.html/
Texas Commission on Environmental Quality
http://trailblazersblog.dallasnews.com/ ... -job.html/
Texas Alcoholic Beverage Commission
http://trailblazersblog.dallasnews.com/ ... -job.html/
ETA on 12/21/15:
Health and Human Services Commission: http://www.texaschlforum.com/viewtopic.php?f=7&t=81136
ETA on 12/25/15:
Office of the Governor of Texas: Per email I just read from TSRA/Alice Tripp
ETA on 12/30/15:
Texas State Guard (concealed only while in uniform)
Texas National Guard (concealed only while in uniform)
Texas Air National Guard (concealed only while in uniform)
http://texaschlforum.com/viewtopic.php? ... 2#p1035030
https://www.txmf.us/jftx-p15-08-persona ... rms-policy
ETA on /1/616: Texas State Comptroller
http://texaschlforum.com/viewtopic.php? ... 3#p1039134
ETA on 3/6/20 Health and Human Services
https://texaschlforum.com/viewtopic.php ... S#p1278578