I'm not sure why we are assuming that the female in question has 'normal' proportions aside from inseam, and will therefore require a shorter top tube and/or bar reach than a male of equal height. Given what we have already been told, I would assume the opposite. I suspect, but this is may never be confirmed, that the inseam measurement might be overstated, but if it is at all close to being correct, then I believe a woman specific design will not help her achieve a comfortable riding position. Here in Portland, taller women ride men's frames and don't have any issue with it. In fact, shorter women ride men's frames as well. It's not about dimensions, its about style. Mixte, step-through style "women's" frames are not built the way they are because women are shorter in general and/or have shorter torsos and arms. "Women's" frames are built the way they are built to accommodate dresses and skirts and a less threatening mounting in general. FWIW.
H