> What can you suggest that has moderate penetration power,
> is lightweight, and concealable and easily retrievable from a purse?

Well, I wanted to get my wife an all metal .380 or the Bersa Thunder, she ended up with the Bobcat 21a simply because it fit her small hands, it has all the qualities you mentioned except penetration power. It is for right hand people because moving the safety while lefty might be too much for some people.