I know this is a very old thread, but I am one of the shorties here, at barely 5'0". I purchased a Specialized Vita Comp in the XS frame, which is the size I needed. I can stand over the top bar (just barely, but enough), and the rest seems to fit me well. So for those who are looking for bike for very short riders, check out the Specialized line and look specifically for models that have a size "XS."