Thinking logically, the FaixChii pairing makes very little canon sense to me.
As many people have said, CLAMP have established the rule that, even though characters belonging to different worlds may act differently because of growing up in a different environment, their heart/soul remains the same. Now why on earth would CLAMP contradict their own rule by pairing Chii with Fai? Chii, as we all know, has already found her one-and-only soulmate: her "Special someone just for her", and that soulmate is Hideki. She spent 8 graphic novels looking for him for crying out loud!
If CLAMP liked the way Chii and Fai looked together I have no doubt that they would have used Chii's poor, loveless twin Freya instead. Thinking logically, would they really trample all over their Chobits series for a pairing that could easily be substituted?
That would make no sense!
Have we had an example yet of a CLAMP character that has a soulmate in one of their previous manga series and has turned up head over heels with someone else in Tsubasa?
No.
Touya is still with Yukito, Tomoyo still adores Sakura, Syaoran still loves Sakura and vice versa, Ashura still loves Yasha, Yuzuriha still has a deep connection Kusanagi. The list goes on.
Why exactly Chii was created we have still to find out. But Fai certainly didn't seem very cut up about leaving her behind at all. A quick cuddle, a few "Good Chii! Good Chii!"s as if she was a some kind of pet and off he went, not seeming bothered that he'd left her dangling in net form above the man that would be after his blood once he woke up!!
We have to conclude that 1) For some reason Ashura is no threat to Chii, even when he is awake, or 2) Fai has little regard for Chii's wellbeing and cares more about his own safety. (Which seems very Fai-like to me)
As for Kurogane and Fai... well, there is definitely something there. What that something is I'm not sure. There definitely will be a reason that Fai and Kurogane shared that look when they first met a Yuko's shop. A reason why Kurogane has made it his buisness to find out about Fai's past and why he won't "Let anyone close" to him. A reason why Fai feels the need to act the silliest and around Kurogane, poking, petting and teasing him. A reason why Fai seems sad when he admits that he knows Kurogane hates him for being the way he is.
If there's one thing I've learned from reading CLAMP manga, it's that every glance could hint at something and every word could mean something later on. I'm very convinced about the AshuraxFai pairing and I'm keeping my fingers crossed super tight for Kurogane and Fai. I'm not expecting any dazzling love confessions, but them remaining together at the end of the series would be enough for me.
