Diners stand in line as they wait to order on a recent Saturday at Cattleack BBQ in Dallas. The idea about barbecue lines started simply enough during our recent visit to Micklethwait Craft Meats in Austin. “Why would you wait in line at Franklin when you can get this so close?” Sherry Jacobson wondered as she ate some of Micklethwait’s brisket, every bit as fine as what you could get a few blocks away at world famous Franklin Barbecue. And there was almost no line at Micklethwait. So we assembled an email roundtable of the Posse, all line-standing veterans, to…