All developers of these codebases need to do is place some ads on their documentation pages and they'll rake in a fortune from the amount of times people have to load it up to remember a class name.

Symfony2's namespacing is a good one for this too:

    \Symfony\Bundle\SecurityBundle\DependencyInjection\Security\Factory\SecurityFactoryInterface
    \Symfony\Component\Form\Extension\Core\DataTransformer\DateTimeToLocalizedStringTransformer

http://api.symfony.com/2.0/classes.html