Mistwalker heading up a new Square-Enix game, be it a Chrono Break or a Final Fantasy (mainline or spinoff)
Remedy making a 'real' Max Payne 3.
Ron Gilbert + Double Fine working on Monkey Island 3 (The real version)
Half Life 3/Episode 3 - Valve. This isn't happening.
Tony Hawk's Pro Skater LEGO - Travler's Tales + Whoever is still around from the original THPS team.
Metal Gear + Metal Gear 2: Solid Snake - Kojima Productions. T_T Sadness.
X-Men Mutant Academy 3 - High Moon Studios, I suppose? I think that's where the people ended up from Paradox.
Star Wars: Battlefront - Frontwire
Avatar: Battlefront - Frontwire
Bone - Naughty Dog. I feel like that amazing character driven fantasy epic would be amazing in game form... that isn't the horrible TellTale game from their early years.
I am sure I could think of more, this is just off the top of my head.