Odd... the Madone bikes on Trekbikes.com (which I assume are 2009 models) all appear to have replaceable deraileur hangers.
I do recall a particularily ugly moment from a few years ago when a local rider (who had a buddy build his bike for him) got his derailleur caught in his spokes and mangled the non-replacable hanger.
Moral of the story: Replaceable hangers are not really needed, unless you really need them.