I am barely 5' 1" and have had 2 wsd bikes with 650 wheels. The second one was a Trek 5200 (precursor to the Madone) 47 cm. I had no issues with this bike. It rode very well.
I now have an x small size Kuota Kebel (not wsd), which is 48 cm. and has 700 wheels. I put 165 mm cranks, and the Specialized wsd bars on (short and shallow drop) in 38 cm, along with the Shimano R700 brakes/shifters. The bike fits me fine and I actually think I could go up to 40 cm bars in this model. I have a 28.5 inseam, if that's any help. I suspect my torso may not be as short as other "petite" sized women. My Kuota has a slightly sloping top tube, as opposed to the Trek, so I think that made a difference. However, it is not as sloping as the Giant bike my friend rides.
Unless you have some special reason, the hype about 650 vs. 700 wheels is just that: hype. I don't ride super aggressively, so toe overlap is not an issue. I ordered tubes from Performance when I had the 650 wheels and I had no issue getting them. There was less of a choice in tires, but I am not so concerned with that.