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.

You can read more about how you can deploy to Heroku from Action.IO here: http://help.action.io/customer/portal/articles/1011326-deplo...

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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.