in general it's only an issue for a kvm development image but this doesn't apply to other images (XEN, vmware, OpenStack, HyperV ...) only to kvm, as 9p is the recommended way to share data from the host with the vm (http://www.linux-kvm.org/page/9p_virtio) would it make sense to build a dedicated kvm-development image which just has the different kernel? it would only be used by developers working on kubic, and not production environments