The kernel-sourcecode package is sort of redundant as the actual source is in the kernel*.src.rpm anyway, but can be built (as i did) by editing the kernel-2.6.spec and changing the line near the top to say "build sourcecode=1" instead of 0.
Make it a conditional define, so one can use "--define 'sourcecode 1'" on the rpmbuild command line to override it. One shouldn't need to unpack the SRPM to change such things. (Also add a suffix, normally nil, that can be overridden in this way to identify custom builds. But I think this is already there.)
