In a medium skillet over medium heat, fry the bacon slices until slightly crisp, 5 to 8 minutes. Drain on paper towels and set aside to cool.
Mix together the mayonnaise, sour cream, Cheddar, buttermilk, parsley, dill, garlic powder, pepper and vinegar in a medium bowl until smooth. Finely chop half of the bacon and throw into the bowl with the dressing. Rough chop the other half of the bacon and reserve for garnish.
Transfer the halved romaine hearts to plates and spoon a good portion of dressing over the top of each, then sprinkle on the chopped tomatoes and reserved bacon.