[url]http://www.games-workshop.com/gws/content/article.jsp?aId=12200090[/url]
the picture of the thunderwolf cavalry on this page, the base a thousand sons head an torso, now unless its from a basing kit which I am pretty sure it isnt, it does not match any of the current available thousand sons models neither the head nor the head dress, so although chaos might not be next it certainly seems they have models ready for them at least!