Joel,
We should have already branched 5.0 when the 4.6 branch was declared closed.
I have work to commit that may or may not be finished by 5.0. I am reluctant to commit it to HEAD because I don't want half-finished work to be released as 5.0.
I think in general we need to have a little more structured plan for CVS tagging and branching.
Its probably a good idea to have a mailing list of people with CVS commit so that we can be sure they are notified of the status of the CVS repository.