User Profile Missing (gives 404)

My user profile at http://twitter.com/svenlatham is missing. I've checked my personal settings - username is correct (and re-saved just to be sure), and I can't find any specific permission settings that would turn this page on/off.

Currently it's giving a hollow bird and a "That page doesn't exist" 404 message. Very odd, I am definitely tweeting from this username but don't seem to technically exist!?