It's a bit of old news already, but Eric Nylund -- who wrote a bunch of Halo-related novels -- claims to be working on a new game for Microsoft. He says:
"What am I working on next? Well, if you took all the best parts of your favorite games, and smashed them together at light speed with your favorite movies and books, you'd get something close to this. It's not announced yet, but as soon as Microsoft does, I can at least tell you the title, genre, and what particular thing makes this game goose-bump worthy. So stay tuned."
There's an extremely off chance Nylund be talking about Project Dimitri? But this doesn't feel right, even if Microsoft owns Lionhead Studios.