We just noticed this approx. 30 minutes ago: Google.com accessed from our Shanghai office shows no search field and the logo is aligned left. Google.cn still redirects to the Hong Kong version at Google.com.hk. No clues sofar on what the reason could be. We'll keep you updated.
Update November 30th: Google.com startpage is back to normal in China. Google China quoted on Dow Jones says it was a "technical error on their side": http://www.nasdaq.com/aspx/stock-market-news-story.aspx?storyid=201011291017dowjonesdjonline000202&title=google-technical-glitch-causes-minor-china-access-issues