We've been hacking on something in this space for the past few months with StackHut - https://www.stackhut.com. We have a demo in a blog post at http://blog.stackhut.com/phantomjs-cloud/ showing headless web rendering-as-a-service.

We've tried to make it as simple as possible to get your code into the cloud. You write your classes and they're deployed as entrypoints into a lambda-esque service that you can call over JSON-RPC - making it trivial to write and deploy a backend.

As described in the blog, the great thing we think it has over tools like lambda is that you can describe your system declaratively, specifying any dependencies you may need, using a simple YAML file and it takes care of packaging your code. You can run this locally or deploy it to our hosted platform where it scales as needed.

Currently support JS and Python atm, and open-source at https://www.github.com/StackHut. We're super early but would love to hear your thoughts.