With all the misinformation out there about Flash not being apart of "web standards" (although without it the web would "break") I found this page on W3 from 2004 that recognizes Flash and Flex as a viable and accessible "canvas" for content right along side HTML Canvas tag (before it was called HTML5),
http://www.w3.org/TR/WCAG-TECHS/ http://www.w3.org/TR/WCAG-TECHS/flash.html
