12 large or 14 to 16 small servings
In a medium bowl, combine the first 5 ingredients; add olive oil, wine vinegar, and balsamic vinegar, if desired, mixing well. Season with salt and pepper to taste. Cover and allow to stand at room temperature for 12 hours.
With a serrated bread knife, cut each bread loaf in half horizontally. Drizzle olive oil from olive marinade evenly on cut surfaces of bread loaves. In order, arrange a layer of salami, mozzarella cheese, ham or prosciuto, and provolone cheese on the bottom half of each bread loaf, dividing evenly. Top each loaf with the olive mixture. Cover each loaf with a bread loaf top. To serve, cut each loaf into six to 8 wedges.
Note: Arrange sweet red peppers on a rack in a broiler pan; broil, about 6 inches from heat source, charring all sides of peppers. Transfer to a plastic bag, seal, and allow peppers to stand 15 to 20 minutes. Remove peppers from bag and easily remove peel, stem, core, and seeds. With kitchen shears or a sharp knife, cut peppers into long thin pieces. Or, use commercially prepared peeled roasted peppers available in most grocery stores.
Note: For six servings, use one loaf of bread, ½ cup olives, 1/3 cup roasted sweet red peppers, ¼ cup peppercini, 2 tablespoons chopped parsley, about 1/3 to ½ cup olive oil, 1 tablespoon wine vinegar, 4 ounces salami, 4 ounces ham or prosciuto, 4 ounces provolone cheese, and 4 ounces mozzarella cheese.