A while back I noticed (you may have, as well) that many book covers were featuring feet, legs, and even shoes! I recall specifically The Paris Wife as one of these. Sure enough, there are observers out there who have compiled collections of book art to document this trend. See this link for a brief treatment of the foot/leg theme, but you must check out the rest of the entry which touches on the “Tiny Men Walking into the Distance” theme- quite funny!
Then I found this link which offers quite a comprehensive list of foot/leg covers. I don’t know how this writer found all these covers, but she claims they are worth reading, regardless of the cover art!