I have toyed with just doing a "Howdah" rifle. I think there was a discussion about an original 16" Double Rifle on Africa Hunting. When I talked to the gunsmith about making a pistol stock, the idea of a removable shoulder stock never came up.

I have toyed in the past, with the idea of a detachable stock for a muzzleloader using a super strong magnet. The project is on hold with so many other "that would be cool" projects. Ive got repros of the Luger and Broomhandle stocks for the same project; but they require more machine work than any gunsmith has been willing to take on.

The Pedersoli muzzleloader has an available stock. Its not "baaaaad" and it does make a good tight fit but I think Id prefer something different.