A while back Tim Sledd, an Andre Galvao black belt and owner of Small Axe Brazilian Jiu-Jitsu, put out a DVD on the Leg Drag. It was met with high praise from competitors and gym owners alike. It opened up a game that few had truly been able to previously explore.
In the video below, we see how Professor Sledd uses the leg drag to combat the elbow escape. Give it a watch, and see if you can add it to your game.