The official website of Blythe has news about their upcoming collaboration with CLAMP.

As previously announced, CLAMP is designing a Blythe doll called B2・HOLiC based on Yuuko’s character from XXXHOLiC. It will be a limited production of only 1000 units.
The release date is set to October costing 26.250 yens. The doll will be formally revealed to the public at the Blythe shop Junie Moon Daikanyama on October 15, where it will be sold in advance.
To celebrate the release, there is going to be a sign session with CLAMP on October 23. More details will be announced later this month.
In addition, an exhibition featuring XXXHOLiC illustrations will be held in Shibuya, Tokyo, from October 4th to 30th.
Excited about the sign session! I believe this is the first one since 2009 in Japan Expo.