Split the bread in half lengthwise. Top the bottom half with the mortadella, capicola, salami, prosciutto and provolone. Toss the giardiniera in a bowl with the olives, peppers and olive oil. Tear out the soft center of the top bread half to make a shell. Pack the lettuce into the center of the bread and top with the giardiniera mixture. Carefully put the two sandwich halves together, pressing to keep the filling inside. Secure with small skewers and cut into pieces.