I'm working on a site, not totally sure what I'm going to put on it yet but I'll cross that bridge when I get to it. Here's my current layout design, it's going to be total CSS/XHTML based. Nearly no images, so speedy load times. Users will be able to submit their own styles, which (upon approval) can be used to view the site. The sublink bar will change depending on what page your viewing/what nav button your mouse is over.
http://img62.echo.cx/my.php?image=site0db.gif