I'm 5'7 (170cm) with a rather short inseam as well ... 28-29". I ride a 52cm Roubaix and the standover height is a non-issue. I wonder where they're measuring it, since these Specialized bikes have quite pronounced sloping top tubes.

Are you able to try out the bikes in person? That would solve a lot of issues ... :/

The standover height on my bike is listed as 756mm and I've never had an issue standing with both feet on the gorund