I doubt the game will run anywhere near that good at that resolution all the time, but it sounds possible to get around 60fps average in few places.
I'm really curious about the effect the motion blur will have on the smoothness of the game. I know they can't create a real film-like motionblur (its impossible without input lag) but it could possibly make the game appear a lot smoother, regardless of the framerate.
Anyway, its all speculation until we see it.
... as if I needed another reason to want a Core 2 Duo or Kentsfield.