The idea is to create a live system, which shows KDE as it's meant to be. Based on openSUSE, but with plain upstream KDE packages, augmented with some demo data and configuration, this system can be used to show KDE at trade shows, be given to users as a teaser, provide a reference for press people looking at KDE, and lot of other cases, where you want to show KDE in all its glory.
A couple of years ago I made a screenshot for a contest showing KDE 3.1.5 in action:
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This screenshot was a success, and won me a price., Now, five years later, I would like to do it again with current technology. Not only doing a screenshot, but a whole live system, and of course with the latest KDE 4.3.1.
We'll have a small team at the conference, which will work on creating KDE Showcase. If you would like to join the fun, there is a session on Thursday afternoon as part of the unconference. Or just contact me directly. Ideas and other input are more than welcome. We'll collect what we are doing at the KDE Showcase wiki page.