This really does not appeal to me at all. The major point of docker containers is not the image format, it's that the kernel can allocate resources more intelligently. VM images work just fine for "shippable images."

What I'd rather see is an allocation layer for physical resources that just cordons off the whole machine (physical or virtual) by tenant as soon as previous tenant resources have been fully consumed, then reclaims hosts after usage subsides. So as a provider I still only have one cluster to manage, but as a consumer I still don't worry about another layer of abstraction slowing things down or pre-allocating resources.