nost: I’ve got an aftermarket top folder on my 870 (Choate) and it does cut down on the length, but the recoil is brutal (compared to a standard stock with pad). Sort of a six of one, half dozen kind of thing.
Definitely more maneuverable in tight spaces (like a hallway) than a full stock.
I don’t know what your budget is like, but Wilson Combat Shop (www.wilsoncombat.com) offers Scattergun Technologies shotguns and they have some really trick s**t (if you’re willing to spend the money).