These are some feet that I made for a friend's Halloween hobbit costume a couple of years ago. They are simply some old shoes covered with layers of pantyhose and some cotton in between. I shaped the cotton and sewed some to make the toes. Added some doll hair for that extra hairiness (not forgetting some on top of the toes of course) and that is pretty much it. (ask if you want more detailed info)
This is one of the funnest costumes that I've been making for Halloween :) In addition to the feet, I made the vest and altered the pants and shirt to go with it.
The same idea could be used to make any kind of feet for costumes. Adding some fur could make an animal costume that much sweeter :D