Over the past month, Engadget has had a three part series explaining how to build an Xbox 360 notebook. The instructions are very in-depth, but it looks like they covered everything there is to be covered.
You now have been taken through the most extensive making-of guide for an Xbox 360 laptop ever written. This information will come in quite handy for your own hacks and should give you the basis with which to create your own Xbox 360 projects.
If you have a lot of time on your hands and a desire to potentially maim your Xbox 360, give the project a ponder.
Source: Part 1, Part 2, Part 3