I think you could play around with a muffuletta to account for cost and regional preference as long as you stay true to the olive salad? I've seen sold in quarter size and on small buns...
laurafuentes.com
Make This Muffuletta Sandwich ASAP. One Bite, and You're In New Orleans
Use this recipe to make a New Orleans muffuletta sandwich at home with layers of meat, cheese, and the iconic olive salad that makes it authentic.