Try the Hard 8 in Coppell. It is very close to Grapevine Mills Mall and has some of the best BBQ near Grapevine. It also has a Texas feel if your visitors are from out of state.
Hard 8 is sorta fun because of the feel of the place. When we first moved our offices to the at area, we took some people from out of town there. BUT, it is really bad food and it is really expensive. If you can find any reasonable alternative, go there.
Main St is the nearest place to get anything resembling good BBQ. But you can go to Bone Daddy's in Grapevine for the view and they do serve some things with BBQ sauce.
Make sure you check what days Main Street in Euless is open- I live about a mile from the place and it is open like 4 days a week- can't remember what days for sure.