MGS4 is going Platinum Hits (Europe equivalent of Greatest Hits) in March, as was mentioned, but has not been confirmed for the US. Considering Uncharted and R&C Future have both been Platinum Hits in Europe for several months, I don't foresee this jump occurring quickly.
My guess is we'll see the next wave around September, after the various video game conventions and before Uncharted 2 comes out.