Here we go again, reinventing the wheel.......
Col. Jeff Cooper discussed this topic to death (it was a quick death) over ten years ago in his "Jeff Cooper's Comentaries". I do know of ONE person that carries a .22 for personal defense, but she does so because she's in her 60's and arthritis prevents her from shooting anything heavier. Cooper said the only place a .22 has a good chance of stopping an attacker is if you shoot them in the eye sockets, and the lady in question can draw and empty her Ruger .22 into a face sized target at 7 yards in very short order!
Jay, can we put up a link to Cooper's Comentaries? It is excellent reading, and I highly recommend it.
On the subject of .22s for personal defense, I like this Machiavelli quote: "Never do your enemy a minor injury."
Or to expand on Cooper's answer to "Do you have anthing GOOD to say about the .25 Auto?"- Cooper replied "It's a GUN!", I would say TWO good things about a .22 for Self Defense: It's a GUN, AND it's better than a .25 AUTO!