What does Single Column Status: ON do?
Several boxes I've set to this have disappeared completely. So don't think I'm understanding what it does.
And what does it mean in conjunction with Left/Right Column Status?

What I want to do is put some boxes up in the header with the search header (currency, language, shopping cart) and put the categories sort of in the middle of the page or to the right of the main page display area but still have a right column for banners and such.

I have seen something like this on http://www.intimateplus-lingerie.com
but I can't seem to figure it out yet.