Suggest a theme that allows joining header to background?

Hi,

I’m trying to find a theme that would allow me to join my header banner seamlessly to the expanding background. Twenty-twelve doesn’t seem to allow this without losing page content margins and padding.

The effect I’m looking for is a coloured container around the page joined to the banner either side. Not an unusual thing to want, I’d imagine, but i can’t find a WP theme that’s designed that way or that can have a straightforward css modification of a child theme.

Thanks for your thoughts – i’ve searched for hours with no luck.