The Kel-Tecs et al. are OK, but not really the same type gun as a TPH, which is a very highly refined, small, light, all steel (I wish alloy-framed) back-up / plinking gun.
The Kel-Tecs and Ruger LCP are fine, but they are slug-ugly and have no single action possibility. (I have and use the Kel-Tec P32). It seems to me they also have an extremely long trigger even for a DAO gun - at least mine does, and they have no manual safety.
My TPH works with any HV .22 ammo with 100% reliability for the last 1000 rds. or so. They do have one problem which is a hairpin shaped double-action spring that is too weak. Easily replaced with a piece of round spring stock bent to fit.
Based on the response I see on the auction sites and gun shows, these would sell very well if S&W could offer them at good quality new for $300-$400.
Should be doable. Mine is a beautiful little Interarms licensed copy, nearly all of the parts are castings which work just fine.