Just poking around on Wikipedia and found this
http://en.wikipedia.org/wiki/Eternal_Darkness:_Sanity's_Requiem
Regarding the possibility of a sequel!

Not sure why it won't post the whole link? Ideas?
Well this bit is the important bit
''Denis Dyack, designer of Eternal Darkness: Sanity's Requiem and Too Human, said "absolutely yes" in July 2006 regarding the question of a possible sequel in his Too Human IGN blog. He stated that Silicon Knights intended for Eternal Darkness to be a stand-alone game, but the company has always intended to make more games set in the Eternal Darkness universe involving the Ancients.[33][34]
At Microsoft's Spring 2008 Showcase in San Francisco, Dyack confirmed to TVG that a return to the Eternal Darkness brand could be on the cards: "There is a chance; we love all the games we work on. We don't want to be pigeon-holed [into a genre], we want to be known for strong content...There's a strong chance we'll return to it, but there's no announcements yet."''
From Wikipedia, obviously.