Endurance Bib Shortby Machines For Freedom
I've read a bit about how they started out and produced this and they have spent a lot of effort into making one of the best female-specific engineered bibs there is!
See their great about page for more specific information about their process. A great tidbit:
In my experience, the chamois doesn't seem to provide adequate cushion to my seat bones, especially during long days. This feeling was reiterated among women I spoke with, and again reinforced by complaints heard by one of the top bike fitters in Los Angeles, Steven Carre with Bike Effect. We started with manufacturers who had specialty lines of chamois for women. Next, we analyzed years of Steven's bike fit data (anonymously, of course!) to narrow the options from hundreds to a dozen chamois.