Projector is an idea I had in May 2010. It is a script that should help you setting up and maintaining a complex projects consisting of many individual components (like, say, an operating system) in a Subversion repository.

(Note: I know that 'git' is the hype today, but I am using Subversion, so that's what I am targeting first. When I'm done, I'll perhaps check out how the concept could be transferred to 'git', but I think the workflow is too different.)