Epic have made it official that they currently have five separate projects in development, but none of these appear to be a new Unreal game. In speaking with Forbes, Epic president Mike Capps, has this to say about the Unreal franchise.
"Unreal and Unreal Tournament continue to have a huge influence on the studio here, even though we're not currently working on an Unreal IP project. Epic's core game making philosophy of "when everyone says it's done, keep polishing!" came from our experiences with Unreal Tournament. That's the beginning of our quality-focused studio DNA."
Hopefully, we'll learn more about Epic's next few projects now that Gears of War 3 is finally done and out the door.