I think S&W should make a Mod 29/629 Carbine.
With an 18 to 20" barrel, which ever balances best.
I would want the barrel profile to look just like the factory barrel, id just extend the 10" barrel out to 18 or 20". Then put a slim round wood fore end on it.
Cut the barrel rib to take scope mounts that are for a regular scope.

The Taurus has a shroud of sorts that is supposed to protect the off hand arm.