Have you tried the state archives in Austin. They are to the right of the capital building and when you enter the state library they are to the right. You will have to get a card to handle some of the things there but once you have it, it is yours forever. I got mine in the 90's and have handled some of the flags. The flags carried by the 6th Texas for example, and the ones captured when we whooped up on Santa Anna. Those are real nice, silk ones. Then they also have the dismounted 17th and 18th cav...Hardee Flag (Blue field and white oval w/ white print unit numbers and honors). It made that tour a couple years ago. But they have all sorts of rosters. Example, I got a Texas flag mat and put it on a copy of the Texas Ranger Roster for the Ft. Worth area, 1860 Texas Rangers.
They really do try to help people looking into the history. Sam Houston's letters are there and you get a picture of a complete different person. I some cases he is a real SOB.
You have a good day, now, ya'll hear.
bh