I really like that background script, might have to give that a try.
If you use Emacs, you might try org-mode - it includes an archive feature that allows you quickly toss subtrees into a second associated text file, which I find handy for keeping a 'done' list.
That's a great script, but it only displays the todo list. Did you hack it to show done items? The author's point is that a done list is only useful if you see it.