Ideally, you want all of your namespaces to share the config data without having to copy it, and you also want them to use the config data in the same way so that you remember they are the same thing when you look at your different namespaces.

This is a good candidate for the Singleton Pattern, which I cover in the issue 0.1 of The Perl Review or Scott Walter's wiki page on Singletons. Basically, your Config class creates an object that everyone can use at the same time in different places without knowing about all the other places that want to use it, and it only ever makes one object so you don't waste space on a bunch of copies.

Since you encapsulate your config information in this object, you only have one config variable in each namespace. That makes maintenance much easier if you decide to change things later.

Good luck!