I find the site layout and theming capabilities in Google Sites (found in the Manage Site screen) very limited; for instance, I do not seem to be able to place the horizontal navigation buttons directly to the right of the logo and to customize their style, as well as to use the standard trick of making a horizontally stretchable background image of a box with rounded corners by splitting it into three parts and replicating the middle one, etc.

Am I missing something? Are there any advanced settings available? Thanks.