Well, a K-Frame S&W cut down to a 2" or 2.5" barrel can make for a real neat carry gun. The .38Spl variants might be a hair lighter than the .357s, especially if you start with an old "pencil barrel" (light barrel) model.
Thing is, the grip length will usually be more than a J-Frame...that's really where the "improved shootability" comes from.
The Colt version of all this will be a "D-Frame", which includes the Detective Special/Agent series which usually had a shorter grip a bit like a J-Frame, but were six-shot like a K. Some Dick Specials had a longer grip, and there were other D-Frames made with bigger grips like a K, in both .38 and .357, but the latter may be somewhat scarce. Colt had plans for a Detective Special in .357 and shipped a few, but then went out of the handgun biz for awhile. They're starting to come back but the small .357 isn't gonna reappear for a while if at all.
I think these critters can indeed be easy to shoot yet conceal well, esp. if you hang wood grips on 'em that won't hang up on clothes. Ted Nugent used to carry a short-tube K-frame .357 for years on the rock circuit, mostly illegally (see also: "God, Guns and Rock and Roll") - without ever having to pull it, thank God, and he never had a problem keeping it concealed.
The J-Frames were popular more due to the short grips and optional concealed/shrouded hammers than due to smaller frames & cylinders, I think.
Jim