It seems it is not just the issue of heat that it keeping Apple from producing the long-awaited G5 PowerBooks.

Apple VP of worldwide Mac product marketing David Moody told Cnet: "It is fair to say that incorporating a G5 into a notebook as thin and light as the PowerBook is extremely difficult."

In September 2004 Apple's VP of product marketing Greg Joswiak said: "The challenges of cooling a G5 in a PowerBook are significantly greater."