gitvimrc.vim

gitvimrc.vim (GitHub: vim-scripts / gitvimrc.vim) by Joel Nothman is a small script that attempts to load a .vimrc file local to the current repository's root when loading a buffer from that repository. This could be used to keep an entire team's style consistent.

It might be worth setting secure if you plan on using this with untrusted open source projects.

Sauce

As an alternative to vimrc management, Sauce (GitHub: joonty / vim-sauce, License: MIT) by Jon Cairns helps manage multiple settings files, which can be used on a per-project basis. For example, running :Sauce MyProject would load the settings associated with MyProject.

Sauce is designed to be used to manage all aspects of the associated settings files, from creation to deletion. Using it this way means it's easy to list all of the current settings files, they're effectively centralised.