Digitimes claims that Apple will be ramping up production of the new 15" MacBook Pro in April, but with the new 13.3" model not ramping up until June:
As Apple will start mass producing its 15-inch MacBook Pro in April, sources from the upstream supply chain have pointed out that the company's orders for the 13.3-inch model are far higher than those of the 15-inch, indicating that Apple is more focused on the 13.3-inch notebook segment. However, the 13.3-inch MacBook Pro will not start mass production until June.
Digitimes also notes that the orders for the 13.3" MacBook Pro is "far higher" than those of the 15" model, though without a frame of reference for the typical mix of Apple notebook sales, it's hard to gauge the significance of this observation.
The April timing falls nicely with reports of new Intel Ivy Bridge chips that would be suitable for use in the new MacBook Pros.
Digitimes, however, doesn't provide any explanation for the discrepancy in the production dates between the 13" and 15" models. It's seems possible that Intel CPU availability may have something to do with the timetable as it was reported the very low power Ivy Bridge CPUs also won't be ready until June. Apple has typically only used these low power CPUs in the MacBook Air line, but the MacBook Pro has been rumored to be adopting a thinner and more Air-like appearance.
Previous reports claimed that the new MacBook Pros will feature a thinner design without an optical drive. We've been hearing whispers about this kind of Macbook Air inspired design since April of last year.
