Apple is separating the new smartphones into its usual low-cost versus high-cost categories, with big differences between the two models coming down to the camera, display, and battery life.
macOS Catalina Now Available
Ultra-Portable Mac Expected at Macworld Expo 2008
The new 13" aluminum sub-notebook is described to be 50% lighter and "strikingly slimmer" than the existing 15" MacBook Pros. To achieve this small form factor, Apple is said to have removed an optical drive from the design of the new laptop. As well, Apple will incorporate NAND flash-based storage as well as LED backlights to improve power efficiency.
Appleinsider posted their belief that a sub-notebook is coming from Apple back in February of 2007. Rumors of an ultra-portable Mac, however, have been ongoing for months with talk of a NAND-based ultra-portable Mac dating as far back as June 2006.
This new description of an aluminum case corresponds to a recent report by 9to5 indicating that slim aluminum MacBooks had been spotted with "something strange" about the touchpad.
Macworld Expo takes place from January 15-18th, 2008 in San Francisco, California.
For what its worth, Apple 2.0 Blog reports that Piper Jaffrey's Gene Munster is 75% certain that an ultralight MacBook or possibly an entirely new product will be coming in January at Macworld. They also point to photos and video of Engadget editor, Ryan Block, successfully transplanting a pre-release Samsung 64GB solid-state drive into his MacBook Pro.