Given the growing complexity of many Python applications these days, developers often use other packages and libraries to help manage this complexity. TurboGears, for instance, will fetch several other packages from PyPi when it is installed and install these packages as well. PyPi provides access to packages that the Python community has provided, possibly because they feel it will be useful in a different context.
However, the PyPi code itself isn't exactly a simple Python package used to host egg files. It is a full-featured, hosted solution. The setuptools package can fetch eggs listed on a simple HTML page. In this case, you wouldn't even need anything other than Apache. However, what would be nice, is a middle-ground. A Python package that uses CherryPy or some other web framework to host the actual packages and provides a very simplistic management interface. I think something like this would be very valuable for packages that are limited by having to retrieving dependencies from PyPi and would need their own repository.
I'm not too sure how difficult this would actually by to implement, I'm only thinking of the need for such a solution at the moment. Perhaps I'll do some experimentation and write about what I find.