pesky-settings is a library for managing application settings, merging data from configuration files and command line arguments and converting to python native data types. Additionally, pesky-settings has an 'action' interface which is useful for constructing hierarchical command sets.
pesky-settings is built on top of the venerable getopt and ConfigParser packages from the python standard library, so it should work on any python you can find (as opposed to optparse or argparse packages, which were somewhat late additions to python 2).