bdist_mpkg is a distutils plugin that implements the bdist_mpkg command,
which builds a Mac OS X metapackage for use by Installer.app for easy GUI
installation of Python modules, much like bdist_wininst.
It also comes with a bdist_mpkg script, which is a setup.py front-end that
will allow you to easy build an installer metapackage from nearly any existing
package that uses distutils.