I put together some code that lets you use your own authentication system with MovableType 3 instead of having to use TypeKey. It isn’t the prettiest code I’ve ever written, but it does work. Version 0.1 can be found over here. It is written assuming that you already have a user database and ways to sign up new users. You will have to modifiy the php scripts to meet your needs and compile some code for it to work. Hopefully someone finds this useful.