Trim fat from meat. If necessary, cut roast to fit into crockery cooker. Sprinkle meat with the salt and pepper. In a large skillet brown roast on all sides in hot oil. Drain. Transfer meat to a 3-1/2-, 4-, or 5-quart electric crockery cooker. Add onions, the 1 cup root beer, and garlic. Cover; cook on low-heat setting for 8 to 10 hours or on high-heat setting for 4 to 5 hours.

Meanwhile, for sauce, in a medium saucepan combine the 2 cans or bottles of root beer and bottled chili sauce. Bring to boiling; reduce heat.

Boil gently, uncovered, stirring occasionally, about 30 minutes or until mixture is reduced to 2 cups. Add root beer concentrate and bottled hot pepper sauce, if desired.

Transfer roast to a cutting board or serving platter. With a slotted spoon, remove onions from juices and place on serving platter. Discard juices. Using two forks, pull meat apart into shreds. To serve, line buns with lettuce leaves and tomato slices, if desired. Add meat and onions; spoon on sauce. Makes 8 to 10 servings.

Transfer pork mixture to covered container and chill up to 24 hours. Or transfer to 1-, 2-, or 4-serving freezer containers; seal, label, and freeze up to 1 month. Thaw overnight before serving. To reheat, transfer to saucepan; cover and heat over medium-low heat until heated through, stirring occasionally. If necessary, add 2 to 4 tablespoons water to keep mixture from sticking.