Sounds interesting. I'd checkout Dokku[0] and Flynn[1] if I were you and see what you could offer differently. I use a single Dokku instance on 5 dollar droplet that hosts all my side projects ect under my domain. I then would extract one out if it ever got meaningful traffic. Another thing to consider is that it seems like the industry as a whole is moving passed the application level abstraction and onto the function level, eg "serverless". Maybe you could jump on that angle somehow.
[0] http://dokku.viewdocs.io/dokku/
[1] https://flynn.io/