I have added support for onImageData and MP3 cover images to Red5. Check out the Jing! I have really big screens so its a large flash video, you may need to resize your browser to see it all.
The example project source is here: http://svn1.cvsdude.com/osflash/red5/flash/trunk/player4/
Also, dont make fun of my code, its just a quick example!