The 2 screen panels are each one of PlasticLogic's 10.7" screens, and they are connected via a double hinge in the spine. The pages could be changed together or separately.
Update: PlasticLogic posted a demo video on Youtube:
I had shot a video showing this ereader in action but unfortunately my camera seems to have eaten it. I'm kicking myself right now because it was a very cool sight to see.
I've always been a fan of really large screen ereaders, though I don't think I've ever seen one on the market. I've always wanted to see an epaper alternative to displaying large-scale documents like blueprints, diagrams, or posters.
Sure, there are things like Microsoft's Surface Table, but staring into a bright light like that is not good on the eyes - not on that scale.