I just grabbed this video off another site where they were talking about WC leg work. I really got a kick out of this (groan --sorry). It goes way beyond what I'm capable of. I have a partially crippled ankle, so I use kicks sparingly and tend to keep my feet on the ground.
Some folks say that you should be able to do just about anything with your feet that you can do with your hands. To which I'd counter, yes, but just as you should avoid "chasing hands", you should also avoid "chasing feet".
Regardless, I found this interesting:
http://www.youtube.com/watch?v=X-iLJJcgopI