+1. .22 is not very good for protection. I carry a .38 spl +p or a .40 S&Wa .22 is fun,but i wouldn't carry one for protection.
i carry a .45...
The glock 26 is a very compact 9. I have one, it will fit easily in any pocket. There are a few glocks that are very small. Another thing you might want to do is go to a public shooting range and see if they rent out guns. Your wife can shoot a few and see what she is comfortable handling.The first rule of a gun fight is to HAVE a gun! That said, a .22 is definitely better than nothing. I've got a little NAA .22 Magnum (MUCH different than a .22 long rifle) as a back-up/better-than-nothing/ultra conceal (palm of your hand) gun. You wouldn't want it as a target gun, that's for sure.
You can find larger caliber pistols in compact/sub-compact sizes that are quite easy to carry, and maybe even smaller than some of the .22 pistols out there (especially the target pistols).
x2 on that.Sig Mosquito is a great .22, I would lhighly recomend them...