Since we've just wrapped up a whole Macworld Expo with absolutely zero PowerBook announcements from the Big Steve, it's evidently time to kick the laptop speculation into high gear. At least, that's all we can infer from the appearance of a ZDNet article by erstwhile MacWEEK staffers Jason O'Grady and Matthew Rothenberg, which delves into the exciting possibilities of Apple's next pro portable, allegedly code-named "Mercury." And for those of you who've been wondering just when Apple would finally cram a full-fledged G4 into a PowerBook, it sounds like Mercury's your baby.

You of course all know by now that anytime you read something about Apple's upcoming products that begins with the phrase "Sources said," you should treat it with about as much credibility as you'd expect from Microsoft on the witness stand, right? That said, there are lots of intriguing little tidbits about Mercury; reportedly existing prototypes are already running at 400 and 500 MHz, but the final version may actually go "as fast as 750 MHz." The chassis is said to be lighter, thinner, and somehow "more streamlined" than that of the current PowerBook, and its screen is rumored not only to be fifteen inches in size, but also to use the widescreen aspect ratio like Apple's Cinema Display. Oh, and did we mention the slot-loading DVD-ROM drive?

Sounds like a serious pro machine to us; if it really ships in the form described in the article, Mercury is clearly targeted at graphics and video professionals who want to crank out quality work on the road. It's a portable Power Mac G4, with none of the compromises typically associated with using a laptop. As such, we expect it'll cost more than a new kidney-- both parts and labor. Our assumption is that the mysterious sixth square in Apple's new product matrix will bridge the gap between the iBook's low-cost, schoolkids-and-consumers design and the Mercury's desktop-in-a-laptop, no-compromises feature list and corresponding jaw-dropping price tag. And if the unseen third portable turns out to be a thin-and-light subnotebook, we (and many others) will praise the gods of product design and sing hosannas on our way to the dealer...