I just bought a copy of the Barbecue Lover's Guide to Austin, by Gloria Corral. Daniel Vaughn, the BBQ Snob, reviewed it a couple weeks ago and he's right. The 174-page paperback is skinny on critical guidance. But if you live in Dallas, like some of us in the Posse, it's also evidence of our lack of barbecue choices.   Corral has write-ups on nearly 60 places within the city of Austin. Subtract the chains (anything with more than one outlet, which knocks out County Line, Bill Miller, Cartwright's and PoK-e-Jo's, among others) and there are still about 35 joints,…