Oh yes, that’s right. I’ve made an inverse Sitecore tree. Despite that it almost certainly will never be of any use to anyone, I’ve made it.
Why? Well, I just thought it would be fun to do. The items that have no children are displayed in a long list, grouped by their common parents. You can expand them to traverse their ancestors. Here’s a screenshot:
Here’s the code (just copy it to a file named InverseContentTreeViewer.aspx):