Given that not many realize the powerful features and polished interface that OpenGrok provides, I decided to put up an OpenGrok server to cross-reference some common major FOSS software stacks on a development machine used by BeleniX folks: http://belenix.v12.su/source/. It contains stuff like the Linux kernel trunk, Python, Ruby, OpenJDK, Glibc among others.
I also have put up patched kernels corresponding to Fedora 13 and 14 releases. It was in interesting exercise to automate getting patched Fedora kernels. Since I wanted as much of history info as possible I did not use tarballs. Rather I checked out the base kernel patch release from Git and applied all the patches in order as listed in kernel.spec and then I did a git pull to merge the fedora kernel git bundle into a subdirectory in the main kernel tree. You can grab the script from here: http://www.belenix.org/binfiles/get-fedora-kernel.
I will add some more stuff shortly. In addition it will take me a few more days to setup an auto-sync mechanism to keep the source trees synced to upstream every couple of days. For now the tress are being manually updated. Hopefully this will prove to be an useful resource going forward.