I haven't seen one. It wouldn't be difficult to put one together but I would be a little leery of a drum screwed into the side of a 15/16" .054 barrel. You would have to make sure the lock supported the drum well. CVA drums thread all the way through the breechplug and give a lot more support than a standard drum.
the gun works dot com offer custom made barrels thru the "oregon barrel works.
They could probably make one up.
I have not heard any bad words about those barrels.
I been thinking of having them make up a .40 barrel for me to put on a trapper or billy parker platform. was looking at about 120 bucks ready to shoot, in the white.