I've been working on developing a fluid, lightweight application layout that is 508 compliant. The design of this blog is based on it. It uses percentage based widths to adjust to the user's viewport width (browser window). EM-based sizing keeps text and images within containers and correctly proportioned through font size changes. Other than a couple of optional images, it uses CSS entirely. The navigation is keyboard accessible
The code and documentation is available on GitHub and contains everything needed to put on a webserver and display. It is provided under the MIT license.
Any issues or bugs can go in the issue tracker.
I couldn't have made this layout without help from the community. Here's a few that I can remember. If I forgot you, let me know and I'll add you to the list.
Matthew Tayler for keeping footers at the bottom of the page
Yahoo! developers for YUI reset and other tips
Chris Coyier for CSS triangles