SharePoint Rich Text Boost
SharePoint Boost are becoming the new market leader in SharePoint webparts and are seeing the real customer needs.
Have a look at one of their less heralded webpart that helps with Accessibility - 'Text size zoom'.
More details available on our Office Talk site http://www.office-talk.com/index.php?id=133
Well priced and as with all SharePoint Boost products simple to install.