Over the years there have been lots of cases offered that were either made especially for TC pistols or carbines, and others that work well with them. So I have a lot of different cases, both hard side and soft cases for my TC's pistols (based on barrel length), and TC carbines/rifles.
For the hard cases, most for the 14"/15" barreled pistols were commonly called silhouette cases and made by several companies, but many of those dubbed as take-down shotgun cases also do work. Many hard cases for generic use will handle the shorter barreled TC's plus extra barrels. Depending on which case they'll hold 1, 2 or 3 fully assembled scoped TC pistols with room for an extra scoped barrel or two or 3.
The soft cases have been offered by TC themselves as well as a lot of other companies. TC's offerings included a black leather case for a 10" octagon pistol along with 3 extra barrels, and the so called Indian blanket case that has room for 1 or 2 up to 14"/15" assembled pistols along with extra scoped barrel pockets. Other companies have offered them as well.
I also have both hard and soft cases for assembled carbine/rifle TC's that have room - 1 or 2 extra compartments for extra scoped barrels.
Your best bet might be to lay what you want to carry in it out on a table and take some dimensions, then peruse the case makers web sites for dimensions to compare. Keep in mind you probably will buy more barrels/frames, so sooner or later you'll want more case(s).
Doskocil, Pelican, Plano, Kalispel, MTM, SKB, TC, Boyt, Allen, Kolpin and Uncle Mikes are just some I can remember off the top of my head that have made cases that work well with TC's. I have, or have had cases from all of them I used for TC's, along with a few custom and airline cases.
HTH