These were sent in as part of a look ahead for Warhammer Fantasy. According to Tim, the next three books are Dark Elves, Dwarves, and Bretons.
Please remember that these are rumors, and salt is always required
via Tim the Thief on Faeit 212
October: Dark Elves
The October will bring Dark Elves with a new Armybook, not Dwarfs!
February: Dwarfs
The Dwarf release has Switched to February
April: Bretonnians