The wings that appeared on Sakura's back in the first volume are the same on their clothes. As you can see, there are 6 sections of each wing, and of course 2 wings to the set.
MAJOR SUPER SPOILERS AWAY! (I don't know/care how to do the box)
Wei Fong Read wishes for the powers of the Tsubasa/Wings so that he can become more powerful than Yuuko, and travel through deminsions and time. He doesn't say why, or how, but he says what he wants to do (might have something to do with the other Syaoran). And while he and the that lady seem to be hostile, it seems they've steered Syaoran and friends out of trouble a few times. ( read everything they say in outo carefully) They want them to find the feathers themselves, and are somehow controlling which worlds they go to. So which leads me to believe they're going to force the group to go to his residence when the search is over, which I'm guessing will tie into the glass scene. I'm guessing about 18 volumes give or take.
hi! well i agree with Anna-san. as for the 12 feathers theory, as Anna-san said, there are 6 sections on each wing and since there are 2 wings, sum it up, it's 12.
i only have scanlations (it's too expensive in my country... ahaha
) and so far, i have up to half of vol13 (no omakes...Â
). i dont think that it'll end in the 14th volume. if so, that'll be so soon. and if it is 14 volumes only, I'll kill CLAMP for making it so short! (Even if I love CLAMP sooo much)
i'm guessing around 18-20 volumes or something. but it's CLAMP's manga so let's just wait for what happens. (I do hope it's a nice ending...
)