Description of problem: kernel-2.6.29-0.12.rc0.git7.fc11.x86_64.rpm package has a quite reasonable size of 24 Megs but for a disk installation it claims 1035938542 bytes. You are reading that right. Something about 1 Gig. A closer look reveals that this happens because all modules are amply padded with null bytes and 'cp -a --sparse=always ...' on this kernel module tree reduces its size from 997M to 76M (with a kernel after such operation still bootable - not so surprisingly). The preceding rawhide kernel, i.e. 2.6.29-0.9.rc0.git4.fc11, has a module tree which takes 188M of a disk space. This is of the same order as with other, relatively recent, rawhide kernels. Still making those modules sparse drops that size down to 78M which is also significant. Apart of gobbling a disk space like crazy these "null fattened" modules make kernel installation scripts to run slow as molasses. Something "interesting" happened with a toolchain?
Recent "2.6.29-0.X.rc1" kernels have module directories of a more reasonable size. Passing those through 'cpio -pmd --sparse' still slims them down by roughly 60% but we are not talking gigabytes anymore.