I don't see this as impossible. Thats how quartz displays work. Just a matter of time before a color quartz type display is invented, if its not already sitting in a lab somewhere.
Digital trickery, yes. He made his desktop background green and used After Effects to composite the background plate, and used tracking points to match the dimensions of the PB screen. Similar, no doubt, to the HP photo commercials.
You can tell from the reflection of the CD hanging on the wall. 😀