Still unsure you appreciate the application need
While I've never (needed) to assess bandwidth requirements for iPad WiFi based mirroring, it's certainly adequate for HD movies on Amazon and I've never seen any loss artifacts from the (probably expertly and losslessly compressed) iPad mirrored display so I don't have any reason to believe that should be an issue. Indeed, it all works just fine with an iPad 3rd Gen and AppleTV. You might want to check it out some day in an Apple store.
We're just interested in the same functionality for Android devices and your responses haven't seemed to be addressing that at all.
I've been using VNC (TightVNC up to now and RealVNC this year when I needed best of breed for iOS and the desktop OS's) for years and I certainly could be mistaken but I don't know of any way to use it for mirroring the iOS (or presumably Android) device's display to an HDMI (room class) presentation display device. Conceptually it would require VNC *server* functionality in the mobile device and a *client* of some kind built-in to the presentation device adapter -- and I'm not aware of any such implementations or plans. It would also be an odd and grossly overcomplicated way to do something pretty simple -- transporting a compressed full-screen image stream from the mobile device to the display adapter. Do you do any wireless mirroring at all and if so using what technologies? With due respect, your answers thus far suggest not.
In any case, it certainly looks like the xBounds and the AllShare Cast devices may do he trick once they're available. If you have any actual experience or clear knowledge of any other promising approaches, please do let us know.