Day 1 Studio's currently running a 30-second clip on their site with a giant robot foot stomping into the ground. Odds are that this presages an announcement about a new giant-robot-suit combat game, since they're touting this as a return to their roots.
The Chicago-based collective last turned out the well-regarded FEAR 3 for Warner Bros. Interactive. The last MechWarrior game from Day 1 was 2004's MechAssult 2: Lone Wolf. That's eight whole years! Time for another one. We'll update this news as more info becomes available.