Much like a pre-pubescent teen blossoming into adulthood, Millennium grows constantly. Here is a gallery of some of its development work, including some of the original doodles.
A few bits of unorganized miscellany for you to sort through. MAY contain spoilers.
Be sure to also join the Millennium development LiveJournal community, an online development notepad for the story, which contains some neat members-only developmental info!