Apple is expected to launch its thinner re-designed Macbook pro models as soon as April according to a report by DigiTimes. The report also suggests that those re-designed models will include both 13 and 15 inch models (no word regarding 17 inch).
Previous reports by the sources suggests that the 17-inch model will be released later on this year :-
Apple is expected to launch new MacBook Pro notebooks with an even thinner and lighter design than existing models in April, at the soonest. [...]
Apple is expected to launch upgraded 13- and 15-inch MacBook Pros in April with initial shipments estimated to reach 900,000 units.
The report also suggests that Apple could gain advantage over its competitor looking to release ultrabooks as Intel’s ultra-low voltage chips destined for those machines may not arrive in time ( at least not until June).
Even though the status of Chip availability for revamped Macbook Pro models as no timeline has been discussed so far, Apple has mostly received good treatment by Intel and judging by that fact. Apple may not suffer such problems by the speculated delay (atleast initial supplies would be provided by Intel ).