There really is a missing link between heroku and aws where one would have more control than on heroku but less devops problems than on aws. And if done right, people would be throwing money at it. I guess that is that elasticbeanstalk and opsworks are trying to solve.
This is what I thought Action.io would be, but after a support ticket where I asked them about this use case, they said:
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"Hi Sergio - Thanks for the note and glad you like action.io.
Please keep in mind however that Action.IO is not a hosting platform - we are a cloud development platform that works with hosting providers such as Heroku, AppFog, EngineYard or Google App Engine.
So like you said, someone fills in this hole, and a lot of people would love pay for it. I don't need to add even MORE services for something as simple as file storage for uploads.
I had heard of Elastic Beanstalk but not OpsWorks. Thank you for mentioning that.
I haven't tried it, but Cloud66 is another provider in this middle ground (they don't host, but provide you the devops tools to do so on amazon, digital ocean, etc.).
I haven't tried it. It does look like a great service. One thing, however, that I don't think it provides is auto-scaling (i.e. provisioning additional servers or removing servers when they are (not) needed). If they were able to provide that, I think it would rule out a need for Heroku completely.