I do not think Thompson Center makes a Renegade Kit anymore in 1-48 and .54 caliber. I think they still make a Hawkin Kit in .50 caliber with that twist but I can understand your wanting a larger caliber. Lyman does not offer a Trade Rifle in a Kit which would be just what you would want. It is in the larger caliber, 1-48 twist with minor brass modifications.

Perhaps Pedersolli has something. Its been a long time since I looked into them. Most of their rifles are assembled but they too used to offer kits. Also check Cabela's. They used to offer a Hawkins in the larger caliber in kit form without all the brass.