I'm 5'1" and rode a Fuji Finest 2.0 44 cm, now I have a Specialized Ruby 44 cm. Do you have a short or long torso in proportion to your legs?

Have you tried any of the 44 cm frames?

As a couple of people have mentioned there are other small bikes out there, even some designed for kids that might work. There was a recent article in Bicycling magazine about 4 bikes that are designed with small frames for kids, and at least one of them has pretty decent components on it.