The simplest way to deal with python package installations, so far, to me, has been to check out the source from the source control system and then add a symbolic link in the python dist-packages folder.
Clearly since source control provides the complete control to downgrade, upgrade to any branch, tag, it works very well.
Is there a way using one of the Package installers (easy_install or pip or other), one can achieve the same.
easy_install obtains the tar.gz and install them using the setup.py install which installs in the dist-packages folder in python2.6. Is there a way to configure it, or pip to use the source version control system (SVN/GIT/Hg/Bzr) instead.
Using pip this is quite easy. For instance:
pip install -e hg+http://bitbucket.org/andrewgodwin/south/#egg=South
Pip will automatically clone the source repo and run "setup.py develop" for you to install it into your environment (which hopefully is a virtualenv). Git, Subversion, Bazaar and Mercurial are all supported.
You can also then run "pip freeze" and it will output a list of your currently-installed packages with their exact versions (including, for develop-installs, the exact revision from the VCS). You can put this straight into a requirements file and later run
pip install -r requirements.txt
to install that same set of packages at the exact same versions.