In a large bowl, stir together the cornmeal, flour, sugar, baking powder and salt. In a small bowl, combine the eggs, buttermilk and jalapeño. Using a wooden spoon, blend the egg mixture and melted butter into the dry ingredients, stirring just until thoroughly combined.
At the short end of a long sheet of wax paper, shape 1/3 cup of the cornmeal mixture into a 4-by-6-inch rectangle. Set a buffalo hot dog in the center of the cornmeal mixture and lift the wax paper up and over the hot dog to enclose it in cornmeal. Pull the wax paper around the hot dog and press to coat the meat completely with the cornmeal, rolling until evenly coated. Remove the wax paper and set the corn dog on a large plate. Repeat with the remaining cornmeal mixture and buffalo hot dogs.
In a saucepan, heat 2 inches of oil until shimmering. Fry the corn dogs 1 at a time over moderate heat, turning once, until golden, about 3 minutes per side. Serve hot with barbecue sauce.