cannot create KVM virtual guests with shared networking?

[James Ralston]

Is it even possible to create KVM virtual guests with shared
networking in Fedora 8?

Apparently, one has to bridge a physical network interface on the host
in order to be able to do this, but virt-manager can't do it, and the
instructions on the KVM HOWTO don't work, either:

https://bugzilla.redhat.com/show_bug.cgi?id=433654

Has anyone figured out what needs to be done to get this to work?

(Using Xen to host a fully virtualized guest isn't really an option,
as the KVM host is my desktop PC, and as such it performs both CPU
frequency scaling and auto-suspending, neither of which Xen supports.)