Episode 26 is up for download at CLAMP no Kyoto Agaru Sagaru‘s official website.
This episode was pretty much entirely centered in Tsubasa and XXXHOLiC, because the last chapter of Nirai Kanai hen was published this month.
Although I’m not secure enough to assume things, it looks like there was a lot of interesting tidbits mentioned by Ohkawa, specially. They also talked about the drawing differences between Watanuki in XXXHOLiC Rei and in Tsubasa (his robe has screentone in Tsubasa) and the difference between Syaoran’s “aa” and “un” answers.
It would be really nice if someone could make a quick summary of what was said, specially during the first 15 minutes.