With a serrated steak knife, slice tops off tomatoes and reserve tops.
Using a small spoon, scoop out flesh and seeds from centers, reserving about 1/2 cup flesh. Rinse out tomato shells; let dry upside down on paper towel. Chop reserved tomato flesh.
In a large skillet over medium-high heat, cook bacon until crisp, about 5 minutes. Transfer to paper towel to drain.
Thinly slice iceberg wedge into fine shreds; chop if long strands of lettuce remain. Transfer lettuce to a medium-sized bowl. Stir in reserved chopped tomato flesh. Add the shredded cheddar cheese, mayonnaise, vinegar, Old Bay seasoning and hot-pepper sauce; stir until well blended.
Crumble the cooked bacon into bite-size pieces. Stir the bacon into the lettuce mixture. Place tomatoes upright on platter. Spoon filling into tomatoes, mounding slightly. Replace tomato tops. Serve the stuffed tomatoes immediately.