The 2.93GHz Core 2 Duo in the new 17" MBP was actually just released which was why the BTO on the 15" Unibody topped out at 2.8GHz when it was released. In Q2, Intel is releasing a 3.06GHz mainstream Core 2 Duo with a 35W TDP replacing the 2.93GHz one and bumping everything down price wise. The current 3.06GHz mobile is a Core 2 Extreme with a 45W TDP which Apple doesn't use.
With mobile Nehalem not due until at least Q3, although it may well fall into Q4, since OEMs have requested Intel hold off to clear inventory, a Q2 refresh of Apple notebooks isn't unlikely. The low-end 15" MBP will probably be bumped to a 2.66GHz 3MB L2 cache model, the high-end 15" MBP and the 17" MBP standardized on a 2.83GHz 6MB L2 cache model, and a unified 3.06GHz BTO option. I would prefer 6MB L2 cache across the board, but I believe Intel isn't cutting the price on the 2.66GHz 6MB L2 cache model introducing a separate 3MB model instead at the same price point as the current 2.4GHz model in the 15" MBP. A 2.53GHz 3MB L2 cache model has already replaced the 2.4GHz model used in the current low-end 15" MBP at the same price point, and the 2.66GHz 6MB L2 cache model in the 17" MBP has actually replaced the 2.53GHz 6MB L2 cache model in the high-end 15" MBP model for the same price so the 15" MBP can already get a processor bump at no cost. But it makes more sense to wait until Q2 and jump directly from 2.4GHz to 2.66GHz and 2.53GHz to 2.83GHz and not bothering with the intermediate steps.