Quadras is a very compact embedded PC powered by a Transmeta Crusoe CPU. It is sold by KWS Computersysteme GmbH and costs 565 Euro (+ taxes) with a 667 MHz CPU, 256 MB RAM and a hard disk.
Ubuntu 5.04 (Hoary Hedgehog) works like a charm, no matter if you take the live cd or install it on the hard disk. There were much more problems trying to use Knoppix or Kanotix.