We need a robust web-based development environment. Think jsFiddle for other languages but more complete. Version control integrated (think github or bitbucket)

We need a robust web-based development environment. Think jsFiddle for other languages but more complete. Version control integrated (think github or bitbucket). Deployment integrated (think heroku). Dependency management. Offline capabilities (probably limited). Technically, i have little doubt it could be possible. No idea what the business model would look like. SaaS/PaaS? A freemium setup would likely be possible? Free base usage, paid extensions? [edit] looks like nitrous.io and/or cloud9 are doing exactly this.