Dave Karraker denied reports that new rumble-enabled SixAxis prototypes have been sent to developers. This somewhat primarily came due to there being a blur on the Haze developer videos.
He clarified that "from time to time", Sony makes minor enhancements to the controllers for our platforms, and recently sent out a new controller prototype that enhances motion and also analogue stick sensitivty.
As a developer myself, I can also confirm this. We don't have rumble!