As Barmijo mentioned in his comment there are other Virtualization providers out there. One of them being The Gridlayer from 3Tera.
The best place to check out what they are offering is to review the demo.
Looks like a good mix of GUI and CLI (Command Line Interface), building the application with drag and drop was also nice. Something for either Amazon or some third party provider to aim at.
The best bit (whilst a demo) was the scaling of resources. Given that it was done using the command line, either 3Tera would offer it or someone else, the ability to scale automatically as load reaches some thresholds with some caveats. Sometimes scaling indefinitely is not the solution to denial of Service or poor written code (of any flavour).