JrockRevolution has just released a new sneak preview of the upcoming episode 3 and it will feature: Anime Expo 2009 Coverage, Versailles (Philharmonic Quintet) and Yuki Kajiura's Kalafina.
Update: (I received word from JrockRevolution.com's spokesperson with more specifics) JrockRevolution and Anime Network's Bento Beatbox Episode 3 will be coming to Anime Network on September 16/17 (on Wed/Thursday's update), and a 10 minute sneak peak version will be available on JrockRevolution's website in early September.