So much depends on your physical build, climate conditions and style of dress regarding selection of a concealed weapon and holster.
The Sig 239 is a good compromise between magazine capacity and size. Overlay a S&W Chief's Special over one and the dimensions are not dissimilar, except that the Sig is slimmer. Same can be said for the now out of print H&K P7.
A single stack 9 is not a bad compromise between concealability, power, comfort and magazine capacity.
Add the S&W 3913/3953 to that list as well. No longer in production, but available used at popular prices....
