For developing purposes I am using now the newest WordPress release – aka nightly builds. I installed therefor the plugin WordPress Beta Tester. (Wow, linking is updated in WordPress editor – you can now make internal links easy by searching for terms or choosing articles directly – nice).
I tested Accessible 1.0 – the WordPress child theme – and MCE Accessible Language Change – both are working with the current developer release 3.1.
I am very glad I discovered your blog (from Accessify Forum) and your attention to Web Accessibility focused on WordPress.
I have developed an accessible theme which seemss to work according to Wcag 2.0 and Italian law 4/2004.
In particular, criterion 3.3.6 about cognitive disabilities is matched.
Please see it at work at http://www.opere.4elementi.info or download it at http://opere.4elementi.info/wp-content/themes/en_ingegno/en_ingegno.zip
The Css makes the widgets valid according to W3c validators, Fae, Total Validator, Cynthya and … my experience.
Please, let me know