This is under active development on the linker branch: https://github.com/meteor/meteor/tree/linker ! The goal, hopefully coming in one of the next few releases, is to provide package-scoped variables and explicit exports from packages, so that you don't need to rely on globals at all any more.
I'm happy to hear this. One of the primary problems with client-side development right now is the lack of commonjs style imports and exports -- something which people are trying to solve using component, etc. It'd be nice if Meteor had something baked in.