Ben Heckendorn the mastermind behind the portable NES and portable Dreamcast rebuilt an Xbox 360 into a laptop. The project took nearly three months to complete, but he managed to pack an entire Xbox 360 into a laptop style case.
Here are the specs:
1) Uses a 17" wide (diagonal) 1280×720 progressive-scan LCD VGA monitor (for HD-level resolutions) Thus you can actually read the text in Dead Rising.
2) Water-cooled with custom-built radiator. Allows for a slimmer main body versus the mammoth heat sinks in a stock 360.
3) Built-in keyboard and Wi-Fi.
4) USB hub allows original number of 3 USB ports for user.
5) All-aluminum case, except for plastic keyboard / ring of light / screen control area.
6) Uses single customized "expanded" power supply brick for both screen and Xbox 360.
7) Breakout ports on back allow hookup to component TV, VGA monitor, sound system (analog or TOSlink) and even crummy composite video.
8) Size: 16.75" x 10.75" x 2.8" Weight: 14 pounds (with water loaded)
The creator goes into great detail on how you can make your own Xbox 360 laptop and check below for a video of the working console.
Edit: Fixed a typo in the original post.