Yeah I was looking at kind of making a heroku setup on my servers sorta like Dokku, but I'm not a real big fan of Dokku. And I wanted to use CoreOS and Docker, but I realized that I can't just include all possible programming languages into a container to be built. So I've opted out of that and just build custom containers based on the app I am deploying.
Building a much more lightweight image for your node app shouldn't be too hard, though. Check out https://github.com/convox-examples/express for a simple example.