Several online shops such as AmiAmi are listing a possible Kobato. artbook entitled Kobato. Illustration & Memories.
The artbook would be released in late September or early October and would cost 1365 yens.
Could it be an artbook for Kobato.? It barely has enough color illustrations to fill one, unless it’ll have extra manga chapters, similar to the Wish artbook? Maybe that’s why it has “& Memories” in its title, as suggested by lovelessinma (thank you for the info, btw!).
I hope this is true, as I wasn’t expecting an artbook for Kobato.
UPDATE: The artbook is confirmed via several japanese online shops. It will have a CLAMP interview and a short story.