When Apple launched its MacBook Air the industry was thrilled by the idea of a super slim laptop that could fit in a manila envelope. The laptop line is so thin that a reporter accidently tossed his MacBook Air in the trash.
Apple.Pro is reporting that Apple is working on a 15inch Air model; this site is also the same one that broke word of unibody MacBooks. Based on the history of accuracy from Apple.Pro there may be some substance to this rumor de jour.
While the idea of a super slim 15inch laptop is intriguing; it would muddy up the line between the MacBook Pro and the Air lineup as the MacBook Pro is relatively thin.
Take the idea of a MacBook Air with a pinch of salt as there have been many rumors that have not been filled that were "leaked" by reputable sites including the iPhone mini, Mac mini updates, iPod touch tablet and the list goes on and on.