WordPress 2.7 is coming with a new backend design. The UI has on the left side the navigation and quite a lot changes to offer.
Since version 2.5 it's already possible to adjust your backend design to your settings. There are many Plugins already out there, which helps the user to adjust their admin to their needs. But mostly are just for color changing or other minor backend changes instead of improving usability.
This is why I want to spotlight the ideas on Konstruktors, which you can watch live online. Note the links below the screenshots.