[libvirt] KVM processes -- should we be able to attach them to the libvirtd process?

Not too long ago we took a patch that allowed QEMU VMs to keep running even if libvirtd died or was restarted. I was talking to Matt Farellee (cc'd) this afternoon about manageability, and he feels fairly strongly that this behavior should be optional -- in other words, it should be possible to guarantee that if libvirtd dies, it will take all the VMs with the "die-with-libvirtd" flag set down with it. I'm not sure this API is portable to Xen, but it would work on any hypervisor that represents the VM as a normal process. Does this strike anyone else as useful behavior? Thanks, --Hugh