Okay, I still don’t have a full working version of Movable Type up and running yet. (I’ve got the blog creation and edit screens working on Windows, but the pages aren’t rebuilding yet. Something to do with the Unix.pm module.) But from what I’ve seen so far, it looks really good. The code is well constructed. The content creation interface is slick. And the things you can do with it look to be the kind of things I want to do with Sunpig.
See the interview with Ben and Mena Trott, who built the system, and have a look at Dollarshort.org for an example of what MT can do.