This is my opinion only:

I don't think barrel length is as hard to conceal as a combo of grip thickness and length. In fact, for me, a Kahr Arms PM9 or PM40 would be perfect if the barrels were 1" longer for more sight radius and bullet velocity. OR, even better, if Glock could make a 9mm or .40 with a width down to .93" wide, like a Kahr. Sure, it'd have to be a single stack but would be much easier to conceal.