Take a look at the Swedish company Xcerion and its XIOS/3 (Xcerion XML Internet OS/3). The OS takes around three seconds to download (1,5 MB size) and it runs in your web browser. A word processor program is just a few hundreds KB. It's free and you will surely see more about it in the future.
On YouTube Xcerion has a video that shows the OS XIOS/3. It enables a networked and collaborative experience with applications utilizing the potential of the Internet.
With the new XML languages it is supposed to be much quicker and easier to develop new applications.
The president of Xcerion, Daniel Arthursson, is some kind of genius saying he during university read a book about one subject and listened on a lecture about another subject. He got 400 university points in four years, normal study pace is 40 points per year. Mr. Arthursson has studied three bachelor degrees at the Linköping University and Linköping Institute of Technology; computer science, business administration and behavioral science.
In a blog post on their blog are some recent updates. (they really have to add auto discovery of the feed)
Q: Where do I download the IDE?
A: The IDE is part of the OS, built in XML and will run inside it (YES you can continue to develop on the IDE within the IDE). It's not part of the initial beta release and will come later on. In the beta release you use a supplied text XML editor.
Via this Swedish article in NyTeknik.