Frictional Games are somewhat responsible for the resurgence in the horror genre after having developed the Penumbra series and Amnesia: The Dark Descent. They also oversaw and co-developed The Chinese Room's recent sequel Amnesia: A Machine for Pigs.
Now they are teasing their next project over at Nextfrictionalgame.com. The progress bar now states it's at 95 percent, so hopefully we'll be getting some solid information soon.