Source from NL said that the new EF 400mm f/5.6L II lens is coming, probably to be announced before this Photokina 2012.
Hope this new lens would include IS, also many people want EF 24-70mm f/2.8L has IS too.
BTW: EF 24-70mm f/2.8L will in stock on September 6 in Japan. And US & EU will available on September 13. You can Pre-order 24-70mm II here.