Great initiative. :)

What do you think about using communities as an existing framework that such a use-case can be added to? So, a project is a community. A lot of the functionalities are already there - there is clear ownership, clear assignment of roles (and existing rules about what role can do what), posts within the community (which can serve as a "project updates" feature), votes and subscribers (which can help identify high-quality communities/projects), etc. And it's already integrated into all frontends. Should be easy to add some custom_json to the community that's specific to making it appear as a project.