So here’s what I gathered so far…
As reported yesterday, XXXHOLiC will have its OAD attached to Volume 14 and will be released on January 16, 2009. That OAD will be Part 1.
Moonphase reports that Part 2 is also scheduled for another limited edition (most likely XXXHOLiC Volume 15, but that’s my own assumption).
According to them, a Tsubasa OAD is also planned. They treat XXXHOLiC’s Part 2 and Tsubasa’s OAD as two separate entities, which means we have at least 3 OADs planned.
When the obi strip of Tsubasa #24 appears we should have more information, stay tuned!