Our customers often send us questions about WordPress themes that follow WCAG (Section508) standards. It happens because they are in need of creating a professional accessible website.
If you want to better understand the WCAG standards you should check the compilation of documents clarifying issues of availability of Internet services: Web Content Accessibility Guidelines
Nowadays many countries establish the law in such a way that public institutions have a duty to customize their websites to meet WCAG 2.0 requirements.
We have preapred a complex article where you can learn more about accessible web site design.
We have already released a WordPress accessible theme!