Well, WoWinsider has confirmed that Wrath of the Lich King is going to be the next expansion to World fo Warcraft.
Here is a link to the article.
Here is a link to worldofwar.net forums where they have information on it also. They say only tauren and gnomes are able to be Death Knights (wtf?).
New link >>>
http://www.1up.com/do/newsStory?cId=3161725