Go ahead award it to one top level cloud vendor, just be sure that the vendor distributes the downstream hardware and software across at least 3 different top tier vendors(and not token deployments of said vendors):
- Data centers: Equinix, Switch, QTS ?
- Hypervisors: VMware, Citrix, (pick some KVM/Openstack supplier perhaps Red hat?)
- Servers: HP, Dell, Cisco ?
- Storage: HP, Dell, Hitchai or IBM ?
- Networking: Cisco, Juniper HP or Extreme/Brocade ?
That cloud can then put their API stuff on top of that stack and go from there.
Not so easy I am sure(I have been working in IT/Operations for 24 years), but at the same time would simultaneously address the outsider's want for more competition and the Pentagon wanting a single vendor. Also is good for the industry in obviously diversifying where the money goes for such a big contract. We are talking about long term stuff here after all.