TechRadar has uncovered some interesting concept art and sketches that the Windows team demonstrated at Mix 09 recently.
The Windows team is notoriously secret about showing any concept designs the team have worked on, usually because of copyright issues and the fact the designs are not protected.
In the first sketch you can see demonstrations for different ways of tiling and arranging windows and thumbnails:
Next up is a sketch of Lava lamps, flowers, faces and some more realistic ideas of how thumbnails could work:
Below you can see a sketching in detail of how icons on the taskbar could work:
The team toyed with the idea of putting previews in the Taskbar:
Calling Batman, previews get projected in a Gotham like way:
Early concepts of the jump lists feature:
From these sketches and concepts you can tell that the team has taken a lot of different user interfaces into consideration. According to Microsoft there were more than 400 sketches of the desktop experience alone along with concepts for how different elements interact with each other.