I wish you could get the actual M1014 with that stock, but you can't in the civi world for less than the price of a used car...
However I've heard from people who use that shotgun at work that they hate the telescoping stock on that thing and that the rifle type stock is much more suited for self defense and general use over the pistol grip as well. The only thing good I've heard about pistol grips for those shot guns is for breaching or in a run and gun situation, but even then I don't think the pistol grip is a good idea on a "tactical" shot gun.
I'd love to be able to afford a civi model m4 regardless.