Wanted - Hawken style stock and lock.

I already have a Thompson Center New Englander 12G muzzle loading shotgun, and a .50 rifled barrel, which I can fit into the shotgun stock, but I would like a dedicated stock and lock for it. It doesn't have to be Thompson Center item - I should be able to adapt any Hawken style stock. Let me know what you've got.

Regards

Luke