I'm not big on 12ga shotguns but I'd buy one or two if I could.
As posted, Hogue markets a few decent shotgun stocks. I'd also check www.deltaforce.com www.brownells.com www.ramlinestocks.com www.midwayusa.com
Rubber butt stocks could be a good way to go. A Surefire foregrip is pricey but worth it for defense/property protection use; www.surefire.com