I expected you to like "tricky" things :-). The problem with z-indexing is that the index varies a lot, depending on e.g. a Category entry.
We used z-indexing when working with BasicInternet:Home to add the social media. And I really like the Category entry, provides me a hint for further look-up.
But the most important one for me would be that the namespace footer "copies" the settings of header/footer from the skin. (not like in IoTSec.no, where the I have white on grey for the namespace footer, and black on white for the page footer)
