How to drag-n-drop like iGoogle?

Railsters:

What's the closest Rail-ist solution for the iGoogle system that
drags-and-drop divs around a page and records their locations? The
draggable_element view helpers would require a system to record
locations, a system to put drag bars on the divs, a system to record
and replay locations, and a system to put dots around target
rectangles?

Has anyone done all that and put the result into a cutesey sample site
or plugin?