i'd really love to see a lead pipe shotgun introduced to the game. essentially being a breech loaded single-barreled shotgun with heavy upkeep needs (it's like an improvised suppressor shotgun, becoming damaged after only a shot or two.)
to balance this high repair cost compared to conventional arms it should take up less space (the same as the lead pipe, 3 slots. maybe make it horizontal so it can fit into pants.)
the crafting recipe would just be two lead pipes and an improvised firing pin made from a can.