Thought I'd join in with my findings.
I have been following this thread since the launch of the iPhone 5 last month and thought I'd bring everyone up to speed with my experiences.
I bought the iPhone 5 when it came out and ever since then my iPad 2 has been acting as an iPhone stand in prior to the release of the lightning connector. I say has been, because a couple of weeks ago the original supplied cable disintergrated (unsurprising seeing as it is made of the most brittle plastic ever invented i think), and i bought a KCU-445i which I can confirm does NOT work with the X305.
I found this out the hard way thanks to Alpine's non-existent description coupled with the fact that it would appear that they not only don't stock the correct part any more, but also fail to make any reference on the website to the fact that it ever even existed in the first place.
Having returned that, I have now ordered "09-14676Z01" which may (or may not be) the same thing as KCU-440i however I can't confirm this either.
If anyone is still after this part, you can get it here
Lightning cable has now also been ordered, so I will update the forum on my findings once everything is in my possession and set up.
Unfortunately, the camera on my iPhone 5 has now died and it is being returned to Apple tomorrow. I'm beginning to think that the gods of car audio are conspiring against me and are determined that I never again listen to anything apart from FM radio.
Hey ho.
For what its worth: iPhone 5, iPad 2, X305 (Not S)