I've been playing with a bunch of the open source CSS frameworks, but I never really found a simple plug and play solution to my problem.
I wanted something where I could pick from a set of common conventions (with/without topbar, sidebar, rightbar, etc.) that supported pods within content areas, and that meant someone who knew very little CSS could still create tableless websites for the vast majority of simple sites in a short period of time using a standard approach.
I've been working with a very smart developer (Thomas Turnbull - expect to hear more about him in the future) to develop a CSS framework that makes it easy to create site templates in under an hour from a JPEG and that I could wrap with a CMS and generator to allow non-technical users to manage their CSS using a nice administrative wizard (that won't be done until early next year) . . .