We first heard of Big Smith's Bar-B-Q after our first East Texas BBQ Tour story was published in The Dallas Morning News a couple of years ago. Several readers wrote to tell us we had missed the best BBQ in East Texas. They urged us to visit Big Smith's, located 8 miles south of Sulphur Springs on on Hwy 154. We put it on the list and intended to get there for a visit. The problem was, we always try to hit two or more joints when we head out of town, getting a sample of BBQ available in the area. Quite…