Lenovo has shaken up the laptop market by unveiling a two-headed ThinkPad, boasting two screens.

The ThinkPad W700ds appears to be the first laptop ever to sport two LCD screens - a 17-inch primary and a 10.6-inch secondary screen.

The souped-up "mobile workstation," as Lenovo calls it, also comes with customers' choice of quad-core Intel Core 2 processors and Nvidia Quadro mobile graphics CPU with as many as 128 cores. It also comes with as much as 8GB of DDR3 memory and a pair of hard drive/solid-state drive bays for up to 960GB of storage.

Lenovo ThinkPad W700ds

It's all in an 11-pound brick - five times the weight of netbooks, such as the Asus Eee 701, and at least double the weight of typical laptops - that is encased in the ThinkPad's trademark ebony exterior.

"This is the nitro-burning drag racer of ThinkPads," said Craig Merrigan, vice president of global consumer marketing for Lenovo, in a briefing this week.

The W700ds is expected to be available in January starting at $3,600.

News about the W700ds was originally timed for release the week of the Consumer Electronics Show (CES) in early January. But details leaked out on blogs earlier this month after a Web page went live early on IBM's Web site.

"Why two screens? Most people are using two monitors at their desktop. So we wanted to give them all the things they are used to on their desk," said Wes Williams, worldwide product marketing manager for ThinkPads.

The primary WUXGA 17-inch screen is brighter and more colourful than other notebook PC screens, Williams said. The main screen is rated at 400 nits of brightness, which is brighter than any other notebook in the market, Williams said. It also has a colour gamut equivalent to 72 percent of AdobeRGB that is better than other notebooks and a plus for photographers and graphic designers, he said.

The W700ds' secondary 10.6-inch vertical screen is about the size of a typical netbook display, Lenovo says, or about 40 percent the size of the W700ds' primary 17-inch display. It can also be tilted up to 30 degrees like a car's rear-view mirror.

The W700ds also includes a built-in WACOM digitizer, also called an electronic drawing pad, and color calibration software. Despite its power and weight, Williams claimed that the W700ds runs "incredibly cool" due to the use of dual fans and dual heat reduction systems.

The tradeoffs? Besides price and weight, the W700ds is bulkier than typical laptops, measuring 16 inches by 12 inches, and is 2.1 inches thick. The ultra-thin MacBook Air, by comparison, is 13 x 9 inches and only 0.75 inches thick.

IDC analyst Richard Shim said the W700ds is a "very niche-y, technical showcase type of product" that will nevertheless likely be a "big hit" with photographers, designers and developers who will value the included productivity-enhancing tools over its shoulder-aching weight.

Lenovo unveiled the single-screen version of the ThinkPad W700 in August. That machines starts with a price tag of about $2,500.

To connect to external monitors, the W700 includes both DisplayPort video adaptors as well as dual-link DVI.

The W700ds is so wide that it boasts a separate numeric keypad, a rarity on laptop keyboards.