It does worry me when people's first response is "impossible", especially as you said "any solution" :)
If you are serious about preventing the saving of text content, you can use Flash or Silverlight to display it, so that it is not rendered as text by the browser.
This way your content is protected from all text copying (except screen-grabbing is still possible).
It would help if you explain the purpose of your requirement as Flash/Silverlight are not good options for mobile devices (which generally do not support them).