Chas,
Make one. Guinness added all sorts of real-steel to his with just a little work, and made his black. Just saw it off, add a pistol foregrip and whatever stock makes you happy, plus a dozen or so shell-holders, and voila (sp?) you've got a nice custom one-of-a-kind tacticool 8mm shotgun for probably less than $250 if you do it right.