I had the opposite dilemma. Im 6' and last year found a "as new" Fx 7.3 Disc for $300 on craigslist - 25". I went to see the bike and the frame was too big but I took a chance on it as it was a steal. Best decision I ever made. The Trek is an awesome bike and I ride it regularly. Its a very reliable bike and I recommend it highly it.
However, Im not sure I would pull the trigger on a 'too small' frame. Aint life weird? Yours is too small and mine is too big