It has been done before, yes. This method is often used to get a total seperation of content from presentation. You can transform the data server side, which grants you a whole variety of options. Let's say you store your content in an XML state. Now, you retrieve it using a server side langauge, and can transform it into HTML. But, you can also transform it into, say, a PDF file. Or a Word file. Or plain text. All of this is on the fly, which means that:

1) You won't actually have several different versions stored on your server
2) If you make a change to the XML data, the change will take place in the different versions that the server creates.

The downside to this method is that the server has to transform the data on each request, but with a decent server this shouldn't be an issue at all.

Can u tell me where i can get free decent xml tree editor...
I need editor that when he process xml file, he show me the content of xml in a tree format, something like InternetExplorer when he parsses the xml file and you can browse the structure, and i want it when i click on some xml tag on the left, that he opens me on the right content for each tag, so i can edit it...i know it's sound silly, but i need it for some simple things