OK, here we go — this is my take on how WordPress dashboard would work the best. All the widgets are expandable, collapsible, sortable and draggable. Widget locations and open/closed states are not stored but that could be implemented easily.
And that all with only 107 lines of CSS, 103 lines of custom jQuery and 10 images (~1.5KB each). Works 100% with Gecko 1.9 and Webkit r35928.
What do you think?