You might want to check out Cervelo's take on the whole women-specific design thing. They believe that there is no need for a "female" frame. Even if you end up disagreeing, it might give you some insight into how to select a frame.

http://www.cervelo.com/en_us/bikes/w...video_headline

i think the bottom line is that she's gotta try a bunch of bikes and find one that fits her proportions. any bike will need to have the right crank length, stem length, bar width, bar reach, saddle fore/aft, and saddle height to match her body.