Many years ago I bought cedar at the lampasas yard that was mentioned, but that's not near San Marcos. There was a place in Johnson city, I think it was called Deleon's, where I bought rough cut cedar. That was all ten or more years ago.
Edit: found it
http://deleonsoutpost.com/There was a guy named Lewis Jasik out by Marion/seguin area who used to cut mesquite logs for me. He would have a blown down cypress from time to time. If you find him take along some Busch light.
One last note, the stuff at Lowe's or HD is a completely different species than the "cedar" that is cut in Tx.