I'm 5ft6ish and my Mountain bike is an 18, BF was dubious at first as my stand over is rather small and my saddle is about as forward as it gets but it's great for me. I love it and feel comfortable on it, I also have shorter legs and a long torso. I can take it around hair pins going down will with no problem at all. I don't know what you are aiming for but for what we are doing right now and probably for the near future what I have is great, we just have to get around to fixing the handle bar too wide issue.
My new road bike is a 52.5cm if I remember correctly (he chose that one based on my measurements and thats it).