Alice: the reason I asked is very simple. I am the project director for the Penkhull Mystery Plays, which is a community drama type of project in Stoke-on-Trent, England. The subject of King Solomon is coming up for a potential script discussion meeting, and I have undertaken to deliver a synopsis of Solomon's life to the meeting tomorrow night. I had this snippet of folk lore about Sheba's legs tucked away in my brain, but I couldn't think where I had read it. Thanks to Emma B's very informative anbswer a few posts back, I now know the facts.
Mudcat, as always, is an excellent source of comment and knowledge.