For people who are interested, yum-3.2.17-0_beta is in the *testing* repo at this moment.
That fixed it! Its installing now...
When Joseph said "when doing an install", I assumed that meant at system install time. I know of no way of doing a pure x86_64 install via anaconda (although I'd love to be told I'm wrong on that).
For installing packages/package groups, then yum comes into the picture.
Yea, I was after a way to install a x64 system only. Seems bizarre that a facility to accomplish does not exist at install time given the requirement exists.
Thanks guys! jlc