I don't see it happening. Webkit is LGPL, and Microsoft have always been anti-GPL. It'd be a major shift in their position to suddenly embrace it out of nowhere

I don't see it happening. Webkit is LGPL, and Microsoft have always been anti-GPL. It'd be a major shift in their position to suddenly embrace it out of nowhere. The Internet Explorer's Trident engine is slowly but surely catching up with its competitors, so it's less of an issue than it was a couple of years ago. Let's not forget IE8 passes Acid2. The real problem for developers it that users aren't upgrading from IE6 fast enough, and that's not going to change whether Microsoft embrace Webkit or not.