Said it before and saying it again. They can do it. A 6 shot 38 +P or even better a 6 shot 327 Federal mag. With the 327 Federal it probably could be the same size as the current 5 round guns. The 38 +P might be just a bit bigger.
How about a .380 semi auto like the Ruger, K Tec, Micro Eagle??
Been there, done that.
Go find a Model 73, I believe it was called for your 6 shot small frame revolver needs. When you get one, post a picture by all means.
As for a .380, the SW380 was a fine little pocket auto, and it had a bottom mag release, which is preferable for pocket carry as a side button can activate from the pressure of tight pants or by knocking against the side of a chair arm, or by contact with the pillar of your car door when exiting the car, etc.
The SW380 was criticized much for its supposedly "cheap" construction - the slide was made of some alloy and "rumor" got around that the little pistol would sort of "self-destruct" after a certain small number of rounds, which of course, was a big load or horse manure, as you find many arm chair shooters say they shoot alot more than they really do.
The fact is that 9mm is equivalent, if not slightly better, than 38 +P and an M&P 9c or a Walther PPS or the old S&W SW9M in the pocket are all better than any .380 Auto. Well, for that matter, Colt had a really dandy 9mm mini auto that was no bigger than a PPK. When you get a 9mm no bigger than most .380s, what is the point of the .380.
The .380 only makes sense in the really tiny pistols, like the Kel-Tec, or its Ruger copy, the LCP.
Remember the advice of Mas Ayoob: "Friends do not let friends carry mouse guns."
