I have started something like this, although I would barely call it alpha at this point. I would be willing to abandon it and contribute my effort elsewhere if there's another project further along or with a better design, but I offer mine for consideration.

https://github.com/eraserhd/acd

It's in the process of being renamed apothecary. It's based around using git submodules for importing other people's code. I was really tired of instructions like, "copy all of these files into your project." (Really?!)

You mean like your "Contributing to acd" instructions? :)