Why wouldn't that be possible by starting from a RIA. I for example don't want an active desktop at all, since I never look at my desktop, it's covered in windows. Looking at it takes the exact same kind of action as alt+tab (a key press). Imho, RIA allows us to think outside the box and benefit from all the good stuff that the web has given us (zero installation, ubiquitous access, standard protocols, OS independence, ...). Downloading software for a site like DZone should only be something you should do if there is a feature that is really not possible in RIA, and even then there should be a RIA version without that feature.
Example: Parleys v2
Login - Parleys.com - a Belgian Java User Group initiative