I just got this idea to create an implementation of Drupal's "Book pages" for TYPO3. I've needed this for some time.
It wouldn't be that difficult as TYPO3's regular page records would be quite suitable. The only thing that would need to be done would be to remove some unnecessary features, rather than add features.
So, after playing around with Drupal for a while tonight, I'm going to brainstorm some ways to get some Book pages working in TYPO3.