Add a $config['plugins']['locale_path'] which can be set to override the individual...

Add a $config['plugins']['locale_path'] which can be set to override the individual plugins' locale subdirectories.
This will apply to *ALL* plugins in *ALL* languages, so should probably only be used when doing site customization...

You'd probably do:

  $config['site']['locale_path'] = '/srv/awesome/data/locale';
  $config['plugins']['locale_path'] = '/srv/awesome/data/locale';

with a structure like:
srv/
  awesome/
    data/
      locale/
        en/
          LC_MESSAGES/
            statusnet.po
            OpenID.po
            AnonymousFave.po

etc, all alongside each other. You could separate plugins from the core if you like.

Where locale files have not already been generated, you can build one for a plugin like so:

  php scripts/update_po_templates.php --plugin=MyPlugin

and pull out the template file:

  plugins/MyPlugin/locale/MyPlugin.pot

Edit that (make sure you at least set the CHARSET, probably to UTF-8) and save your customized .po
files into the structure as above, and use msgfmt to generate .mo files for final output.