My recommendations for a concealed carry .357 magnum would be the Smith & Wesson 640 or the new M&P360.
Smith 640. The smaller boot grip will also fit on this firearm.
If you don't mind a used gun, the Smith & Wesson Model 13 (blue) or 65 (stainless) in a three or four inch barrel is an excellent choice. It is a slightly larger K-frame and a six-shot, as opposed to a 5-shot like the 620 and 360.
Smith & Wesson Model 65, 3-inch
If don't mind a larger firearm, check out the model 327, the 327 TRR8, and the 327 Night Guard and 386 Night Guard. All these models are larger frame, short barrel models, except the TRR8 shown below.
Model 327 TRR8
Have fun choosing, let us know what you decide to go with.