Saltlick Barbecue Rest. down here in Texas uses pecan "shells" (not hulls) when they hold the meat before serving. The shells are soaked and thrown on wood coals in an open pit. Those shells seem to put out a whole lot of smoke!
Also, they use Southern Pride's in the back for their main cook, in which they use pecan wood and oak combination ... and yes, I do know this for a fact.