In kernel26, we try to cover the common use cases as much as we can - this is not a common use case, but rather a corner case. I suspect that including this into kernel26 will bring disadvantages to users that don't need debug symbols (at least kernel size, maybe also speed).

Creating a separate kernel26-debug is lots of maintenance, but not many people will use it.

Unless there will be a large number of requests for such a package, we will probably follow Arch's usual policy: It's something rare, so the users build it for themselves (which you already seem to do).

You might try to convince me otherwise, if you feel any of my above statements is false.

No, I admit that for now, it's not something a lot of people I know use. Debuginfo is extremely useful for systemtap, which I needed when I noticed its absence from arch.
It's the first thing I've been missing from other distros for now, so I wanted to know if that was a choice or just something not done because no one asked for it before.

Maybe it's time for me to bite the bullet, do an AUR myself and see if anyone is interested :)

Anyway, thanks for taking the time to explain this to me.

Yes, that's probably a good idea: Put it in AUR and see how many votes it gets.