Perhaps, but both the Mozilla and WebKit stylesheets are available for reference in their respective repositories (and likely unchanged, for the most part), and

Perhaps, but both the Mozilla and WebKit stylesheets are available for reference in their respective repositories (and likely unchanged, for the most part), and IE9's purported stylesheet is here: http://www.iecss.com/ http://www.iecss.com/ It would be doable to keep up to date if someone wanted to, though whether it's worth the effort is another thing entirely.