Multiple authorized resellers this week are reflecting stock outs of 15-inch MacBook Pros, suggesting that Apple is ramping down production of existing models before introducing redesigned offerings that will largely resemble the company's increasingly popular line of ultra-slim MacBook Airs.

Among those resellers reflecting backorder status on some of the current 15-inch MacBook Pros is J&R, which is now sold out of both the 2.2GHz model, which is listed as "out of stock," and the 2.4GHz variety, which is currently advertised as "on order."

In addition, Best Buy has also stopped accepting online orders for the 2.4GHz model for home delivery. The 15-inch notebook is still available on a store-by-store basis, however a quick check of individual store inventory in cities such as Chicago and Austin similarly indicate that between 40 and 60 percent of those shops are similarly reflecting stock outs.

Earlier this week, MacConnection was temporarily out of stock the 2.2GHz model of Apple's 15-inch MacBook Pro, but the notebook has since come back in stock at the online retailer.

Multiple instances of inventory constraints within Apple's indirect sales channel are often some of the first signs that the Mac maker is drawing down stock and slowing shipments of existing models before replacing them with materially enhanced offerings. This week's stock-outs come as Intel is gearing up to launch its Ivy Bridge chips, which have been rumored to begin finding their way into Apple's Mac product line as early as this month or next.

Apple appears to be planning a staggered overhaul of the MacBook Pro lineup, beginning with an updated 15-inch model, followed by the 13-inch, and ultimately the 17-inch by the end of the year. AppleInsider reported in February that Apple plans to give priority to the 15-inch MacBook Pro model in updating its lineup of professional notebooks.

Recent rumors have claimed production of the 15-inch model will begin this month with 200,000 units, while production of the new the 13-inch MacBook Pro will occur in June with builds of 400,000 initial units.

The new 15-inch MacBook Pro is rumored to arrive as soon as this month with Intel's Core i5 and Core i7 Ivy Bridge processors. Reports have suggested Apple's new notebooks could include Intel's Core i7-3820QM and Core i7-3720QM models featuring integrated HD 4000 graphics.

There are fewer details on the forthcoming 13-inch MacBook Pro, as one report from March said it was "not clear" if Apple planned to introduce a new MacBook Pro with an entry-level Core i3 Ivy Bridge processor. All of Apple's current "Pro" laptops feature only higher-end Core i5 and Core i7 processors.



An illustration of Apple's notebook lineup planned for the 2012 calendar year.

And even less has been said about a new 17-inch MacBook Pro, as that notebook is expected to launch sometime after the 15- and 13-inch varieties. Apple employed a similar approach in late 2008 and early 2009, when the 15- and 17-inch MacBook Pro redesigns were spaced about three months apart.

The new MacBook Pros are expected to be noticeably thinner and lighter in design, and will eschew the spinning disc drive to adopt a form factor similar to Apple's thin-and-light MacBook Air. The MacBook Pro lineup was given a quiet update with faster GPUs and graphics cards last October, while the last major redesign of the lineup came in late 2008.