Combine mayonnaise, sour cream, mustard, onion, horseradish, and dill.
Slice baguette in half horizontally. Spread the cut surfaces with mixture.
ham, roast beef, salami, dill pickle slices, tomato slices, Swiss cheese, and pepperoncini. Place top half of baguette on filling. Cut sandwiches into pieces. Serves 6 to 8.
Trim the fat and calories by using light mayonnaise and sour cream.