String Calculator Kata with No If's

A friend (James Thigpen) issued a challenge to me today... Let's try to do the String Calculator Kata without a single if statement. My last blog post was about wanking code (aka code cuddling) so this seems an appropriate balance. ;D

You can get more information on the kata here: http://katas.softwarecraftsmanship.org/?p=80

Refactorings would be awesome, I have a nagging feeling it doesn't need to look this ugly.