In a large bowl, combine the beef, onion, oatmeal, cornmeal, bread crumbs, salt, sugar, egg, tomato juice, water, barbecue sauce, 1/8 teaspoon liquid smoke and vinegar. Mix together thoroughly and place mixture into a lightly greased 9x5 inch loaf pan.
In a separate small bowl, combine the ketchup, brown sugar, mustard and 2 drops liquid smoke and mix thoroughly. Spread over the top of the meatloaf.
Bake at 350 degrees F (175 degrees C) for approximately one hour.