The only intall I would be able to do 100% over the net assuming a working current linux install is gentoo. This is because there is no "installer" program that needs to be run off a bootable CD or anything. You can just create a partition, unzip a tarball, chroot to the new environment, set up the new OS, install grub the way you want, reboot, and pray to god you did everything correctly. I know of no other distro that would allow one to do a 100% net install the way I described. That being said, there may be a distro or two you can do this with that I just don't know about. I think this isn't much harder than setting up gentoo right infront of the box, and you sound like you should be able to do it with lots of reading, and a slow, cautios approach. You can read all about the normal Gentoo install process here: Gentoo Handbook
, and then adapt it slightly to your unique requirements.
If you have physical access to the box, or someone else does, you can put whatever you like on it. Because you know redhat, that may be best. I fell in love with gentoo, and in my eyes, there is no
other distro that even comes close
. 30% of the reason I like it is the isntall process, the other 70% of the reason I love it is because of emerge/portage, it's package management system. No more dependency hell, no more RPMs, no more slow-as-hell precompiled binaries (well, that last part is optional). Give gentoo a try, I think you'll really like it.