Tsubasa:
The tankoubon edition of Tsubasa #28 has 9 additional pages from the epilogue chapter that were not printed in the magazine.
cutesherry scanned those pages and uploaded them here. The translation from those pages by starlady38 can be found here. Make sure to check them out!
The final Tsubasa volume has 268 pages. I think that’s the largest tankoubon released by CLAMP to date? I don’t remember how many pages RG Veda #10 has.
I was happy with the additional pages because they reveal a bit more about Fei Wang Reed’s origins and somehow give a more satisfying idea of who he was.
Kobato.:
Here’s the cover of the first Kobato. TV Anime DVD (taken from the series’ official website):

There will be a customer service available for those who buy DVDs 1 to 6 where applicants will be presented with a bottle made of glass just like Kobato’s.
The limited edition of DVD 2 will come with an original Talk CD featuring Kobato and Kohaku, while the limited edition of DVD 3 will come with an Ioryogi plush toy strap (check the picture at the official website).
Lastly, Kadokawa will release an official guide for the TV series entitled TV Anime “Kobato.” CHARACTERS COLLECTION. This will be released on January 29.