Place beef in slow-cooker. Combine remaining ingredients, except rolls. Pour over meat. Cover and cook on LOW 8-9 hours.
Refridgerate or prepare sandwiches now. Shred beef by pulling it apart with two forks; add 1 cup sauce. Reheat in microwave or on stovetop. Spoon on warm, open-face rolls or buns. Top with additional warm sauce, if desired.
This may be cooked a day ahead and refridgerated overnight. Skim fat off top and reheat.