A: Nowhere that I could find in town. As Fred Paz, manager of wholesaler Tortillas Mexico (which has a retail outlet at 840 West 11th Avenue, 303-623-7875), points out, "Once you start getting involved in animal fat, the FDA has to be involved, and there are a whole lot of regulations you have to deal with." As a result, area wholesalers and the handful of local eateries that make their own tortillas either use vegetable shortening or, for a fresher taste that keeps longer, no fat at all.