Recompute and other neat "green" technologies are competing in the Greener Gadgets Design Competition, hosted by Core77 (you can vote for your favorite green gadgets):
Rather than making a large tower constructed from numerous materials (ABS plastic, aluminum, steel, etc.), hundreds of manufacturing processes, and dozens of individual components, the Recompute case is made of corrugated cardboard (recyclable and renewable). There are four low-impact manufacturing processes to assemble Recompute: Die cutting, gluing (with non-toxic white glue), printing and electronic assembly. Recompute uses only three major electronic components: A motherboard with processor & memory, power supply, and a hard drive.
From the Upcoming ueue, submitted by zeo.
(though metal shielding (inside) requires less material/resources, than metal cases)
http://www.engadget.com/2009/02/05/recompute-a-closer-look-at-the-sustainable-cardboard-pc/