NSA + VMware = Crackproof Computing?

n8willis writes: "ZDnet is reporting on a VMware and NSA collaboration called "NetTop." The idea to run multiple virtual computers on one box, to eliminate the need for government workers to have separate PCs--and indeed separate networks--for classified and unclassified data. The challenge is making the virtual barriers as secure as the physically separate networks. NSA and VMware say they've done it. What do you think?" Will copying between virtual machines be impossible? I wonder when (or if) NSA changes will make their way into the various distributions' boxed releases.