Well, I don't know about Trek/Bianchi, but I know for sure that you will fit a Specialized women's road bike 44cm if you are 5ft tall. I am 5ft1in and just made it to the 48cm Specialized Amira (I felt slightly cramped on the 44cm and I wanted more bottle cage space).
2014 Liv Lust
2013 Specialized Fate Expert with carbon wheelset (sold)
2012 Specialized Amira Elite
2010 Santa Cruz Juliana with R kit and Crampon pedals (sold)
2011 Specialized Ariel Sport,suspension post,Serfas Rx Women's Microfiber saddle (sold)