[libvirt-users] Changing default nic and storage types

Hi, Simple question that I can't track down any notable discussion about, let alone an answer... Is it possible to define what the "default" nic and storage types are? I am deploying images out of cobbler using koan and all of them are running virtio wherever applicable, but this is not the default, and at present there is no way within koan or cobbler to define what type of devices they should be. I've hard coded this device type declaration into koan, but don't like that in the slightest, and would typically expect to be able to just set "default=virtio" in a libvirt config file somewhere. I fear I'm actually not missing anything and it's just hard coded for the most compatible device with no recourse to override it. Thanks Chris