I was playing around with trying to get the Wikipedia content area in full-screen. I ended up coming up with a very-very light skin idea while doing so.
An anti-skin where the content of the page takes up 90% of the space on the page. The only UI present is a top ui bar (think somewhat like Google's navigation bar). The right has a site icon and potentially some types of navigation. The right is a little bit Google style in how it has a button for the user that opens a bubble/pop-up/pop-down with user links. We may place the search bar beside it.
We may also have a 'lite' version of it that's not an actual skin. Instead it would be a js gadget, it would add a full-screen icon button to the upper far corner (right corner in ltr) and when clicked change the page to look more anti-skin like, but since it has to overlay with another skin doesn't have the full functionality and the navigation bar doesn't do too much besides provide you with a way to return to the skin you're in.