How will this work? It sounded like a user could just build a custom VM image and send it to you. There wouldn't be a way to deploy that to heroku, right?
Are you doing sort of a blended app hosting/cloud offering?
Have you seen the dotcloud "build files" for specifying services? I wonder if trying to encourage standardization among cloud/app hosts on a service specification file like this would be beneficial, similar to Gemfile/Procfile/etc.
Are you doing sort of a blended app hosting/cloud offering?