In updating its PowerBook G4 line Monday, Apple reiterated that a G5-based laptop is still a ways away, CNET News.com reports.

"It is fair to say that incorporating a G5 into a notebook as thin and light as the PowerBook is extremely difficult," David Moody, vice president of worldwide Mac product marketing at Apple, told CNET News.com on Monday.

While the current PowerPC 970FX processor Apple uses in its Power Mac G5 systems has power management features that would help in developing a mobile G5 system, Apple is looking not just at sticking the 64-bit processor in a portable package, but providing a solution as light and elegant as current PowerBooks.

At present, a PowerBook G5 would "be this really thick, heavy notebook, and it would be loud as all get-out," said Kevin Krewell, editor in chief of the Microprocessor Report. "Those would not be design choices that Apple would want to pursue."

While Apple managed to squeeze the G5 into the two-inch thick iMac, halving that width is proving to be a daunting task. Last month, Apple VP Tim Cook called a PowerBook G5 "the mother of all thermal challenges."

Michael Gartenberg, an analyst for Jupiter Research, said he would be surprised to see a PowerBook G5 in 2005.

"A G5 PowerBook is going to happen, but not as soon as a lot of people would like," Gartenberg said. "Apple is concerned about preserving the entire mobile experience, as opposed to just putting a G5 in a box and sticking a handle on it."