What kind of barrels. Several makers will take any barrel and fit it to a TC product. Bullberry? ... As said, you are adding metal and machining same and this costs alot of money. You would probably be happier with something they have already mass produced. But you can ask. Eabco.com? I think Virgin Valley Guns is out of business. Google TC specialists. SSK?
Someone, and I apologize for not recalling the name, was making a "female" adapter to fit into the TC gun with a precise hole and then making barrels to drop into that hole and headspace properly so you have a gun with adapter and a collection of barrels that drop in. Of course you are limited a bit by rim size and a few other considerations, but, say, .308 family would start you with .243, then .260 (unless you wanted a .25 Souper wildcat), 7/'08; .308; .358... I think there is a .338 Wildcat... This might turn up in a search. luck.