I've done a proof-of-concept mod that detects if a form has saved data and fires a user-defined function, rahter than restoring everything regardless.
In my example, I display a "restore" button and a "discard" button for each form. Restore restores just the data for that form. Discard does nothing yet.
You can see the example at http://marxjohnson.github.com/sisyphus/
The code is in the gh-pages branch of my fork. It can definitely be improved. I don't have the time to work on it any further at the moment, but I intend to come back to this in the future.