I saw applications like: http://icloud.com and http://www.eyeos.com and they seem to work great in a browser, I think this should be created with Flex. and who knows the same app ported with AIR to run from the Desktop. Eventually this application can be make bootable and work as a real OS or some kind of virtualilzed client from a web browser.
Can't wait to see Adobe taking this to the next level, imagine all the power of you OS in a Browser window, using resources of a Cloud Computing, or maybe just using resources from your Linux Host for small offices. Maybe booting with a Linux and use all the desktop as Flex/Air Desktop, that would be really awesome !!!.
The eyeos demo is down.
But, from what I saw at iCloud, there is no reason you can't build an interface like that in Adobe Flex. A few people have asked me for a "Flextras Desktop" which includes thing like a task bar component, a window manager /MDI, a start menu, etc...
If you're looking for the same sort of thing, I'd love to talk to you more in depth about what you would use it for and specific features that you'd need: http://www.flextras.com/?event=ContactForm