Erik, this is a great idea and one that not only engages students but gives them a challenge. I agree with Maria in regard to using different color pens for each draft or to edit their drafts. The editing process, marking up their first, second and possibly a third draft, will help them to see how they have progressed. They should keep all drafts while they work on their final. Again, this will help them to see progress and stay away from starting from scratch.