Preheat oven to 350°. Without separating rolls, cut each package of rolls horizontally in half; arrange bottom halves in two greased 13×9-in. baking pans. Sprinkle each pan of rolls with 1 cup cheese. Bake 3-5 minutes or until cheese is melted.
In a large skillet, cook beef and onion over medium heat 6-8 minutes or until beef is no longer pink and onion is tender, breaking up beef into crumbles; drain. Stir in tomatoes, mustard, Worcestershire sauce, salt and pepper. Cook and stir 1-2 minutes or until combined.
Spoon beef mixture evenly over rolls; sprinkle with remaining cheese. Top with bacon. Replace tops.
For glaze, in a microwave-safe bowl combine butter, brown sugar, Worcestershire sauce and mustard. Microwave, covered, on high until butter is melted, stirring occasionally. Pour over rolls; sprinkle with sesame seeds.
Bake, uncovered, 20-25 minutes or until golden brown and heated through.