Does anyone know if it would be possible to use extJS to make a skin for roundcube? It would definitely look great! :D For example:
Feed Viewer 3 (http://www.extjs.com/deploy/dev/examples/feed-viewer/view.html)
I don't know the answer to your question (though, I would doubt it was possible) but that extJS (engine?) is very cool.
-berylium