Jul 12, 2011 09:02 GMT  ·  By

Leaked Apple-internal part numbers indicate that new MacBook Airs are on their way on July 14. The systems will come pre-installed with Lion, Apple’s latest revision to the Mac OS. Thursday may finally see OS X 10.7 released to the public.

Part numbers for unreleased Mac computers have been obtained by Mac-centric blog 9to5mac courtesy of a certain Mr. X who reportedly said that Apple will be releasing four new MacBook Air models.

There will be two configurations available for the 11-inch model, and another two for the 13-inch model.

The ultra-thin laptops will not boast any major aesthetic changes, this person said, while the major enhancements are expected to be in RAM, CPU (Sandy Bridge), and connectivity (Thunderbolt).

They’re also coming pre-installed with OS X Lion, according to the latest rumors, as well as this source.

But there’s more.

Also in accordance with said rumors, 9to5’s source says there’s a batch of new Mac Pros on the way as well.

Same recipe: more RAM; new CPU architecture; Thunderbolt; and the recently-rumored rack mountable design to justify the extinction of Xserve.

Since Apple also has to apply the latest Intel-treatment (Sandy Bridge and Thunderbolt) to the Mac mini range, new models of the low-end desktop computer are expected to drop this week as well.

With Apple rumored to have held off the introduction of its latest MacBook Airs in order to launch them in tandem with Lion, it only makes sense to introduce the latest Macs and OS X Lion on the same day.

Whenever it ships, OS X Lion will be a $30 upgrade for Snow Leopard users.

It will be downloadable through the Mac App Store, and will require an Intel-based Mac with a Core 2 Duo, i3, i5, i7 or Xeon processor and 2GB of RAM.