I just got an e-mail from the TBS iShop website and there are more details on extras!
Limited Special Extras (I'm guessing they only come when ordered through the TBS iShop...?):
4 Random Postcard set
Adorable Usa-chan/Kuma-chan muffler towel here
Special Extras (I think that comes with every DVD):
Bonus Disc (tentative)
★Honey's movies (from the official website) ame to muchi (the corners where Chiba made drawings and Nakamura made up quotes for them)
★Hikaru・Kaoru Attack！Off-shoot Interviews
★Collection of TV spots and more!
Pre-orders are collected on the website until 12/16 (December 16) until 12pm. Purchases from the iShop may only be for those residing in Japan.
for your help XD