Ron,
the polymer-framed Kahr PM9 (sp?) pocket pistol is highly regarded among folks who with CCWs.

Most folks caution against small of back carry.. forget why. fall and get hurt?

I tend to carry IWB holster or belt slide holster strong side right with untucked shirts, a Glock 23 .40s&w, which is compact variant of the full-sized Glock 22 .40
Summertime or when i'm just wearing shorts i'll carry in a shoulder bag.

Some also caution against the really small Sub-compacts, they tend to favor reliability of the full-sized pistols.

Once you get it you can experiment with different carry modes.. see what works best for you.

On my CCW i can specify 3 guns.. how bout yours?
G'luck.. let us know what you get!