Another new theme on request of Martin - it is labeled A-Default-Widescreen.
It's the same as the current default theme (Inspire) but it will go to 100% page width no matter how wide your screen might be - so there should be little if any background image visible to the right or left side of the screen.
The theme author tells me he is working on a "dark" version of the same inspire theme, and as soon as that is out we'll set it up and find an easy way to toggle between light and dark versions of the same main theme.