rpath in setup.py?

[Marc Recht]

>       ext_modules=[Extension('struct', ['structmodule.c'],
>           runtime_library_dirs = ['/opt/python/python2.1.3/lib'] <= added
>           )],

Did you try the following already?
...
  extra_link_args = ['-Wl,-R/opt/python/python2.1.3/lib']
...

Marc