> They share many patches, but RHEL gets a lot of stabilization work and backports.
Well, yes. And I agreed with you there.
> However, RHEL kernel is very clearly NOT branched off of Fedora's kernel.
So, your theory is that Red Hat have a completely independent RHEL tree in house and they have some secret society test just those kernels for years, before they become real RHEL kernels. I think you are mistaken. They would not have enough man power or wide enough configurations available for that. Their "super stable" RHEL kernels would suck big time if they did that.
Instead, Red Hat let new kernels into Fedora for community to test (for instance, people running F-17 are testing 3.5.x for them right now, people running F-18 what will become 3.6.x etc.). Then, at some point, dictated by internal release schedules of RHEL (i.e. the mysterious dates RH employees sometimes slip into public domain), they branch that off and start stabilisation work, based on various patches from older/newer development.
Otherwise, what's the point of having Fedora? They are not doing it only out of being nice, I am pretty certain of that.