Good idea in theory
Mossberg has an interesting new package out for their model 500
My reservations are two-fold. First, i don't like the pistol-grip only configuration. It's not a good configuration for effective shooting especially if the user practices very little with the gun.
Second, i'd like to know more about the associated knives and hardware. There is a lot of crap out there masquerading as heavy-duty multi-tools or "tactical" knives.