Check out Tsubasa 226!
http://www.onemanga.com/Tsubasa_Reservoir_Chronicles/226/01/
Real Syaoran is shocked to learn his clone is also his father? No he doesn't seem to understand it himself... although, thank goodness Sakura stopped him from "putting an end" to the evil clone, when she did. Otherwise real syaoran never would have been born so his dad never could have been cloned and.... etc.
Also, Fei Wang seemed shocked to know that Yuko was dead in EVERY world, which has reawakened my insistance that Sakura's mother Nadeshiko is a Yuko from her world (She looks a lot like the failed clones of Yuko that Fei wang made) and that the reason Fei wang put the death magic pattern on Sakura in the first place was too get the attention of her mother. Only Syaoran and Sakura's mother could see the marking afterall. And when Syaoran asked her "Do you know who did this to her?" Didn't she reply "no, but I think he knows (another) me."The Yuko he knew! That's my theory any way.
So he's been trying to clone, and search the worlds for a living Yuko. And now what will happen?
as well as Holic 185:
http://www.onemanga.com/xxxHolic/185/01/
Yuko is such a bad influence on Wata-kun XD Well, This brings up a few theorys fans have presented. Is watanuki actually Clow reed? Or a reincarnation of him? Hmmmmmm....
Enjoy!