Use pybundles to push dependencies
It's not nice requiring that the server have access to a cheeseshop that has all the necessary python dependencies on it. That means that for packages you've created, you either have to put them on pypi or run your own cheeseshop. The download and dependency resolution steps also introduce more opportunities for failure at deploy time.
I've looked at the pybundle feature included in pip, and I like it.
So part of pushing a site will be pushing the pybundle of the requirements, then installing it into the remote virtualenv.