I have these
http://www.rei.com/product/725342

Not sure if the fleece lining disqualifies these for you as too warm. They are very thin- like raincoats for your shoes- and frankly not very warm, which is why I tend to use my neoprene shoe covers instead.

there's a useful thread here (discusses quite a few other options):

http://www.bikeforums.net/archive/in.../t-360161.html