Intel announced a new Core 2 duo processor running at 3,06 GHz. Contrary to that of the same frequency that is already equips the current (and precedent) iMac, its consumption will be only 35W maximum compared to 44W. This new thermal envelope should make it possible for Apple to propose it as an option in its MacBook Pro high-end.
It is also possible that Apple ignores this and prefers to focus on the next generation of portables which will change radically the architecture while passing to Nehalem by the end of the year.