About a year ago the Accessibility Kit for SharePoint was announced but lately some new options became available to built an accessible website on SharePoint. One of them is the Alternative Rendering Framework (ARF) for SharePoint. Another option is the Barriere-frei kit for SharePoint (BKS).
BKS was developed according to the Access for All (AA+) guidelines and will help to make the Internet more accessible. For example BKS helps to annotate pictures with a meaningful description, which can easily be accessed. Screenreaders use the html-<header> tags to figure out the structure of a page. If there is a WebPartZone is place on a page this structure is broken by static <header>-tags produced by the WebPartZone. The BKS includes an alternative to the WebPartZone.
The already existing Accessiblity Kit for Sharepoint (AKS) targets to solve the problems described above. The BKS has other technical approaches,offers more flexibility and better performance.