Just when you thought there were no new tricks left in the laptop world ... along comes something previously deemed impossible.

With the ThinkPad W700, Lenovo offered the first notebook with a built-in pen tablet and a color-calibration system. Now it ups the ante again, with this enhanced version of the W700 — the W700ds — the first laptop to offer a secondary screen, built right into the back of the primary display.

I use the term laptop loosely, of course, because they haven't invented a term to describe what this machine really is. Portable computer might be more appropriate: The 11-pound W700ds would crush the femurs of most undernourished geeks, and it's clearly designed to be parked on a desk (and, given the nearly $5,100 price tag, secured with a sizable chain, too).

If you read our review of the W700, you'll grok our thoughts on the tablet and color-correction features of this machine. Here they seem wholly unchanged, and again the gorgeous, incredibly bright 17-inch display is more than ready to collect your average Pixar animator's drool.

If he's a real spitter, why, just reach to the right side and pop out a secondary display for more real estate — here you get a bonus 10.6-inch LCD, not as beautiful as the primary panel, alas, oriented in portrait mode. While jaws drop when this trick is first performed, in real life the secondary display doesn't have as much utility as you'd think. You can park IM windows here and whatever toolbars you use (obviously this was created with Photoshop jockeys in mind), but it's generally too small for dropping web pages or your e-mail client.

Under the hood, the W700ds has been quietly upgraded to a 2.53-GHz Core 2 Extreme and dual 200-GB hard drives. The 4 GB of RAM, 64-bit version of Vista and Nvidia Quadro FX 3700M GPU remain the same as the pitifully mono-screened W700. With its newly enhanced firepower, the W700ds broke all of our general-app laptop performance records (nearly 15 percent faster than the W700), and it rocked our gaming benchmarks too. For the permanent record the scores on PC Mark05 were 8449 and PC Mark Vantage were 5490.

Ask the W700ds to give you all the power in the world, and it complies. All it asks for in return is, like, all your money. And a ruptured disc or two.