This trailer was showed on 'Nico live' about an half our ago. I recorder it with Hypercam myself so well here it is! Shakugan no Shana III Final will be broadcasted at October 7,2011.
@About the Japanese text flying through the videos.. those are comments which other watchers wrote, it somehow was showed in the video, lol. ps. also sorry for the bad quality my hypercam sucks.