Shifter Theme System for Wordpress is a complete theme system for your site. Just watch the movie.
Shifter has 13 module positions, 15 skins, 4 body width layouts (including fluid width), 6 sidebar width and location options, and an optional 3rd column setup - all with the flip of a switch.
The Shifter Theme System will change the way you organize, design, and manage your Wordpress site forever.