I have been working on a case for a Raspberry Pi. The Raspberry Pi is a small single board computer that runs Linux. You can check out a few videos describing the board and the Raspberry Pi Foundation's goals. My plan was to make a pocket sized clam-shell palmtop computer similar in size and inspired by the HP-200 LX palmtop computer from 1994.
The plan is to have both a screen and keyboard. It is currently powered by 2 18650 batteries in series. Here it is running off the batteries with a screen. The screen is relatively cheap and was sold as a screen you would have in your car showing a camera for use as a backing up camera system. As such it is designed to be powered from a cars 12 volt battery. I have mine running straight from the 18650 batteries. See Cheap Miniture LCD Screen. Also on this page is a link to converting the screen to run from 5 volts. It seems as if the screen internally runs at 5 volts but has a regulator to drop down the 12 volts coming in from the car battery. A cheap circuit board with a switching regulator chip bought from ebay regulates voltage from the batteries down to 5 volts to power the Raspberry Pi. In the picture I have the power hooked straight into the GPIO see the pin-out here. However, I think in the future I will power the pi via a powered USB hub (which can be seen just above the Raspberry Pi board in the photo below) instead of directly into the GPIO.
a 4.3 inch LCD via HDMI that is used in the HTC Desire HD.
Another note on power consumption: At some point I may try and swap out one of the chips on the Rasp Pi board for better battery life. A 3.3 volt regulator can be desoldered and swapped out for something more energy efficient. Check out some info on that here and here.
I decided to make the case of 2mm think aluminium. Below is a knock up held together with tape to see if everything fits.