Many people that came to our Drupalcon booth (#73) yesterday, where impressed from our laminated case studies and asked if all those case studies ware available on our website. Well, now they are ;) . Attached to this post are all the featured case studies on a PDF format. You can download each one separately, or you can download all the showcases in a single PDF file (called case-studies-all.pdf).
The Sparkeo - case study was also promoted as a detailed show-case at Drupal.org front page around a year ago - http://drupal.org/node/722208 .