> What if we had an "enterprise" version like GitHub which you could run on your infrastructure?
You might want to look into how c9 ( http://c9.io/ ) does it. They have a similar stack to yours. The core of their product is open source. They accept contributions, which lowers their cost to develop. They keep a few choice features (integration with github, etc) for their hosted/paid version.
If you open sourced your core product and kept a few features for your paid solution (versioning, saved output, etc.), you may gain the momentum you need.
You might want to look into how c9 ( http://c9.io/ ) does it. They have a similar stack to yours. The core of their product is open source. They accept contributions, which lowers their cost to develop. They keep a few choice features (integration with github, etc) for their hosted/paid version.
If you open sourced your core product and kept a few features for your paid solution (versioning, saved output, etc.), you may gain the momentum you need.