So after Del Toro's announcement that he'd be at the very least writing and producing The Haunted Mansion, which he hoped to direct, he revealed that that film will have to wait for the moment. He's going to be busy mastering the period horror film At the Mountains of Madness, based on the H.P. Lovecraft book. This project has been rumored to death, and many thought that it would never happen because of the way the story is put together. However, when you need a studio to give you the utmost trust, even if it's undeserving, there's only one man to go to: James Cameron.
Yes, the self-proclaimed "KING OF THE WORLD" has opted to produce the film, giving us assurances of top notch visual effects, and giving Guillermo free reign to do what he wants to do creatively. Horror films usually don't get such a high budget, but Del Toro is taking that leap of faith that it will work. I personally haven't read the H.P. Lovecraft novel, but I'd like to so I can get some sort of idea in my head of what this story is, and what the film will be. Best of luck to you Guillermo Del Toro.