I agree that there's a difference between them, but it's hard to say why. Possibly the initial locative in (a) puts focus on the postposed subject, and that focus is what makes it more tolerant of being followed by modifiers. The test of that would be if focus in other positions sounded more like (a) or (b):
(c) It was a woman tall and beautiful who stood in the doorway.
And yes, I feel this has the literary quality of (a) without the oddness of (b).