We had a similar need at my company. Basically how can we upload “closed source” packages to an index while being able to install them as if they were on PyPI?
We have sponsored a project called devpi which acts as a PyPI cache (packages you access from PyPI will be cached on your server) as well as a powerful and fast index server. The documentation is available at devpi: PyPI server and packaging/testing/release tool.
Next on the roadmap is mirroring for multi geos deployment. To kick the tires on your machine takes about 5 minutes (look at the quick start guides). Finally, devpi is compatible with both pip and easy_install (i.e., you do not need the devpi client installed on your machine).