I suspect StageWebView in AIR 3.6 will be able to handle acceleration since it uses the system's WebKit. However, I haven't done any testing with it so this will be something you'll want to try out. As far as I know, the built in version of WebKit (provided with AIR) does not support this.
Thanks a lot, actually I tried AIR SDK 3.6 yesterday and it seems it still doesn't support an acceleration. In a browser it works just fine even in fullscreen (zoomed page). It seems that the best way to achieve my goal will be using Cordova wrappers for OS X and Win Desktop. But as an AIR developer I really want to use AIR SDK So I will do some more tests..
Thanks for the update. Are you using the htmlloader or stagewebview class?