Hi!
I have the same or similar requirement, with the additional difficulty that the frames I wish to drag between are in different browser windows.
JQuery-UI does not support this at the moment.
However, it seems to me this should be doable, by using HTML5 drag n' drop support.
See the demo at:
http://decafbad.com/2009/07/drag-and-drop/api-demos.html#delegatedThis works pretty well (I tested in Firefox), and even between different windows. Depending on the type of data being dragged, you can even drag to the desktop or other applications.
The code for the demo uses jQuery, but not jQuery-UI-draggable. Instead it uses the HTML5 drag and drop stuff.
Seems like a nice solution, but a little different to jQuery-UI-draggable. It's more about transferring the data during the drag, and less about the visual effects and DOM nodes.
While I am planning to stick with jQuery-UI-draggable for the moment, in future I will look to switching to the HTML5 solution, since being able to drag between windows is a very compelling feature for my application.
Regards from Vienna,
Richard