> There's no reason why building a custom kernel should be considered to
> be any different from building, eg, a custom glibc.
I'd bet good money on needing access to kernel source to build something
(typically a driver, e.g. for the NVidia and centrino drivers)
you can't use kernel-sourcecode package for that, nor do you need it, so
this part of your argument isn't correct.
or
switch on-off some options being a couple of orders of magnitude more
common than building a custom glibc.
which is one shell command away via rpmbuild -bp ....
you need to enter a few dozen shell commands to compile a kernel anyway,
is one more such a big deal ?