For the next part of my work for my thesis I am going to be implementing phase 2 of PEP 302 in the pep302_phase2 branch in svn. Paul Moore has graciously volunteered to help me (and more people are welcome to join if they know the import machinery already; sorry, but I need to get this done so I can't use this as a way to teach people stuff).
Going to start with making built-ins and frozen modules be meta_path importers. That will help me get used to the import code. Plus it is self-contained so can be done in a relatively isolated fashion.
But after that is when the real design work begins. =) But I will worry about that when that point is reached.