We don't have a direct way of getting the pixel data back and forth from a panel.
You could try to get a socket connection via the Connections SDK and get pixel data that way. Not sure how much effort that would be. There is an AIR example in the connections SDK but I'm not certain if the socket interface will work inside of the SWF Panel.
Telling Photoshop to write them out to disk and then read them into your panel would probably be pretty clunky.