I highly doubt that CLAMP has no idea. I remember reading it and Ageha Ohkawa said something like "So there is a desire for this pairing?" CLAMP are evil in that way, I seriously don't think that they were completely clueless...
Totally agree.
Regardless of whether or not I think KuroFai will end up canon, I don't believe CLAMP had no idea. They're not that innocentÂ
. I mean, CLAMP characters are usually paired up with someone, and shounen ai is common with them. And Kurogane and Fai look a LOT like Kakei and Saiga from Legal Drug, who were blatantly together. (...I guess this is just a personal opinion, but I think they do, lol!)
And the question "so there's a fan desire for this pairing?" doesn't necessarily mean they hadn't ever thought of it. It could be CLAMP just testing the water, seeing the fans' reaction. After all, CLAMP never gives ANYTHING away. It's not like they'd say "oh, yes, eventually they'll get together". They're very ambiguous, those girls.