[cpr]

Yes, there's a whole portion of the Amazon Cloud that's run entirely for government (a family member is a higher-up at AWS Gov), and I have to assume they're also running private clouds with physical security, but I have no idea.

[toomuchtodo]

It's the GovCloud AWS region.

http://aws.amazon.com/govcloud-us/

[emidln]

IIRC, GovCloud is available for general purpose usage by private companies, it's just expensive and not as flexible.