Hi!

As far as I can see there is no kvm in the base repository but
the older version 36 in CentOS-Extras. Version 83 that belongs
to 5.4 is only found on the install DVD and CD-Set.
So it's different when installing kvm later with yum which results
in kvm-36 than choosing 'Virtualization' on DVD install that
installs kvm-83. 
It's also a difference between installing from network and DVD,
even when the same Kickstart file is used when kvm is selected.

What is the reason of the base-repo/media difference?

cheers,
Brian.