I'd just want to challange your thought that she has a short torso....I'm 5'8" with a 34" inseam and I don't consider myself to have a short torso. I ride a regular trek madone (07) size 58cm (actual measurement is 55cm seat tube/top tube). I've shortened the stem though. Admittedly I've been professionally fitted to a regular size 54cm trek madone in the 08 model. Just a thought as you continue your process here.