Part of the reason for this is that we don't yet have enough icons to pull together a cogent header that won't end up looking cluttered. We need more nominations! (Especially if you have icons with more negative/blank/background space—that would be amazingly helpful. Take a look at our current header, and you'll see what I mean.)
To that end, we'd also like to ask the icon/graphics makers out there: would you be interested in giving us a link to your icons and blanket permission to use whatever of yours for the header? We would of course give you credit and promise only to use your permission for this one purpose: a new header for the community. Y/Y?