The Being John Malkovich web site has a section on the puppeteer that did all of the amazing marionette work in the film, including QuickTime movies of his show. (The whole web site is pretty cool, actually. Also check out JM, Inc. Sign up, get free stuff--assuming they haven't run out already...)
Many thanks, Lisa, for mentioning Mermaniac: A Show Tunes Weblog! You know what I like. :) Via Mermaniac: BradLands will soon have Specific Overtures, dedicated to musical comedy. Got the Sunday poster and everything. I'm so glad I'm not the only one...