The Japanese website digitalcamera.jp received a confirmation that the upcoming Nikon D4s camera will have the same memory card configuration as the D4: one XQD and one CF slots. Here is a comparison of the memory card door (the D4s is on the left):
B&H already has a listing for the Nikon D4s on their website. There is no price or specifications, but you can sign up with your email for future updates: