yeah, my ones just basic principles of using window events to track mouse positions and using the document object model to manipulate a styles settings.
The one you provided a link for is quite slow because of the transparency effect, and it uses a block of text as the click point for dragging whereas I just left it as the entire layer.
I was thinking about writing a windows emulator script so you can have layers that move, snap, close, minimize, maximise etc.
Don't know how much use it would be to people tho.
I have an idea from 4 years ago: A Web Desktop. With documents edited online with favorites , bookmarks,email and rss feeds all from your web desktop. Your script is fitting very well in this ideea. I also starting with scriptaculous with some dragabble layers for a photo editor online. soon will be ONLINE

Regards