On a Miyazaki message-board, fans are discussing and linking to two magnificent papercraft models of Howl's Moving Castle (from the film of the same name). One is a free download (though, bizarrely, it is a PDF in a Windows self-extracting archive, ugh) while the other is a $50+ book.
(Thanks, Jesse!)
Update: Gabriel sends us direct links to the Mac download, and the Mac instructions download