Last September, Epic Games Technical Director Tim Sweeney said Unreal Engine 4 wouldn't "see the light of day until probably around 2014." That may still be true, but by the sound of it, we'll be treated to a preview much sooner than that.
G4TV quotes Epic Vice President Mark Rein as saying, "People are going to be shocked later this year when they see Unreal Engine 4 and how much more profound an effect it will have." Rein didn't reveal more details, so it's not clear exactly what we'll see or when. (I'm excited all the same, though.)
We caught our first glimpse at Unreal Engine 3 back in 2004, roughly two years before the first UE3 game—Epic's own Gears of War—hit store shelves. So, getting a first look at Unreal Engine 4 a couple of years before its release actually sounds about right. Perhaps we'll see it demoed on Nvidia's next-gen Kepler GPUs, since UE3 was first shown running on a GeForce 6.
The newest bit of Unreal Engine technology we've seen lately is that awesome-looking Samaritan demo. However, Epic has made it clear time and again that that demo is based on Unreal Engine 3, so Unreal Engine 4 could be even more technologically advanced and visually impressive.