"Note that this will only work for modules with simple names, not for the ones that have the double colon (::) in the name. For those modules, you will still have to provide the appropriate subdirectory tree."

This is not true. For example: /your/module/directory/Special/Module.pm will be accessable using:

use lib "/your/module/directory";
use Special::Module;
[download]

Update: maybe I don't get your comment right, but I don't see what you mean with "provide the appropriate subdirectory tree."