Sony has just released a new teaser video for the second generation Digital Paper, the DPT-RP1. They showcase the great responsiveness of the note taking system, which seems like a drastic improvement over the DPT-S1. Sony has also developed split screen view, where you can do a number of interesting things such as compare revisions of a document or have a PDF open on one side and take notes on the other.
The DPT-RP1 is powered by a CPU is a quad core Cortex A5, which is why the page turn system and note taking functionality is so robust. The DPT-RP1 is going to be released this June in Japan for $700.