I am not an expert on the 11th Texas Infantry, but in 1998 I did write a history of the 28th Texas Cavalry (dismounted) that served for much of the war in the same brigade as the 11th Texas. If you would like to read a brief history of the 11th, I would suggest going to the following website:
As far as I know no one has written a full-length history of the 11th Texas. The Texas State Archives does have the "11th Texas Infantry Description Books" in its collection. It has been more than ten years since I looked at that resource; I'm afraid my memory is a bit hazy in regard to those records. However, I recall there is a listing of officers in these ledger books--I believe it even lists ages and birthplaces for the officers. The books contain a number of strength reports--telling how many men were present, absent, in arrest, detailed, etc. for specific dates. There are also some inspection reports in the books. If you have a serious interest in looking at the descriptive books, then I would suggest that you contact the Texas State Archives and find out in more detail what information is in the books
The Confederate Research Center does have a file on the 11th Texas that might have some items of interest.
Other than that, I cannot think of any major resources relating to the 11th Texas other than the compiled service records. If you are trying to find a death date for your ancestor, officers sometimes sent lists of soldiers who had died to newspapers. A number of Texas newspapers are available on microfilm and could probably be obtained on interlibrary loan. The Center for American History at the University of Texas in Austin has an excellent collection of Texas newspapers on microfilm. Good luck on your research!