OK, I know I'm going to kick myself when I see the answer to this, but my brain is fried today and I just can't think of the answer.
What I want to do is have a header like this:
for the repeating background, I've got a background picture which I want to repeat if they've got a small screen resolution (ie 1280x1024 or 1600x1200). The background picture is a photo I've taken and doctored to fit the look I want so I want it to start after the logo. I want the header to stretch 100% and the picture to repeat on the X axis if appropriate.