Mark just posted a blog about top-down design here: http://spaces.msn.com/mgroves/blog/cns!43AFE059FDA652E!1179.entry
This is so typical of Microsoft. Mark came in and said, "Show me the value!" and after throwing various TechNotes/Documentation at Mark, including those on Shadow Applications and Agile Development, Mark was asked to make it better so that others like him get it.
Therefore, please help Mark by answering the questions on his blog.