Skaven and High Elves is confirmed for the core set...
High Elves get a Griffon, Skaven get the Plague Mortar/Launcher/Catapult thingy haha...also 40 Clanrats and 20 Slaves...
Also, before the naysayers... when I say "confirmed," I mean confirmed to me from very reliable sources. So you can choose to take this confirmation with as much grains of salt as you want...haha...