If you have a Pietta 1860 and want a belly gun, check with VTI. I think they might have the 1860 snubby barrel for around $75.00. It is not listed in the parts break down so you will need to e-mail them about it. They carry the snubby barrel for the 1861 so they may just have the barrel for the 1860.
Take off your long barrel, put on the short barrel, presto, belly gun.