According to the official website, a Blu-ray box set of Toradora! was announced to be released on December 21st. An unaired episode will be included in the box set. The price is 39,900 yen ($1 = 77 yen).
Let's see, if I remember correctly (It's been a while since I watched it, so correct me if I'm wrong), we've already had a beach episode, a pool episode, I'm pretty sure they already went to a hot springs but I could be wrong, and a school festival episode, so it can't be any of those (again, if I got all of those correct. I'm not sure about the hot springs or the school festival).