Most of you will have heard of Ben Heck who created the XBOX 360 Laptop as well as many other portables out of the full size original's such as the Playstation 1, N64, PS2 and much more. His site is over here.
The latest is the Atari Jaguar. Unfortunatly the Atari Jaguar was a real flop. I know... I sold 1 the whole time I worked at EB, and it got returned under their 10 day returns policy. Anyway, a good customer came along to Ben and he couldnt refuse. Full instructions are included so you can make your own. Hopefully you wont and will decide to make something else on his site 
Via: Engadget, Instructions on Ben Heck