Tattiefritter - do you ride a specialized? your description sounds like my Dolce!

If she's atheletic and flexible, she'll probably want a slightly longer TT like I did. On my Terry (which comes with a 50.2 TT), I had to move my saddle all the way forward for my short legs and then get a longer stem (110mm). It works perfectly because the 650c wheels allow for less fork rake and that, combined with the longer stem gives me awesome handling. My Specialized which had 700c wheels and a larger rake (so no toe overlap), had more sluggish handling. No big deal for longer touring rides, but when I wanted to keep up with the spirited lunch rides with the guys, it annoyed me. On the Terry, it's not an issue.

FYI: I have 650c wheels, a 48 cm frame and now an effective TT length of approximately 54 cm.