I just found out, care of this io9 list, that there was an At The Mountains of Madness project in the works at one point. It had Guillermo del Toro wanting to direct, James Cameron agreeing to produce, and (less interestingly) Tom Cruise. And it fell apart.
MAN that’s a pisser! That’s easily my favorite Lovecraft work. I’m not certain it would have maintained its charms beyond book form, to be honest. And maybe from that point of view it’s good that it didn’t happen. The mystery of not having really seen what the protagonists saw there adds a significant amount of tension to the whole ordeal. But….