KPackagekit won't search for packages or display list of packages
any more!
Two particular behaviours that I've noted as probabally related are
that 1)When I go to refresh the list of updates it reports that it is in an "Unknown State"
and 2)when I close KPackageKit by pressing cancel the backend is left running.

Since you haven't had any replies yet I'll kick off with perhaps not the most useful advice...

I am afraid I don't know the package but it is bound to have an rc file (kpackagekitrc) which you could rename and start the package again.

toad wrote:I am afraid I don't know the package but it is bound to have an rc file (kpackagekitrc) which you could rename and start the package again.

I think that the issue is in the actual packagekit back end. After reinstalling all
of that the issue went away.
Non the less the whole thing still feels flimsy and over worked.
I'll forgive it for being in beta mode. Yumex (a gui for yum) is giving me a pleasant
graphical package management experience at the moment.

The yum backend has a tendency to wait for things that never happen. Its not a bug with KPackageKit, but with PackageKit/yum.