Disclaimer: I’m talking about my startup :)
StormForger (https://stormforger.com) is cloud based Load Testing as a Service.
If you like to create test cases using a JavaScript DSL, run load tests and performance analysis and let us take care of all the provisioning and data analysis stuff: feel free to sign up for our private beta. Just drop us a line if you have further technical questions.
Talking about big numbers in this thread you may want to read this thread as well: https://news.ycombinator.com/item?id=7920930