Making extensible Grails applications

Is there a way to make a Grails application extensible without giving out the source code to the application? The idea being that I want end users to be able to add functionality through custom made modules.

I found this, but near the bottom it says:

It is still unclear to me how an extension could add a plugin it needs or modify the Spring or ApplicationContext on the fly without a restart. The Grails roadmap suggests that there would be a hot-deployable plugin infrastructure in place soon, which might solve this question.

The closest thing I found on the Grails Roadmap is this (as a "theme" for Grails 2.0):

Take modular development wi开发者_StackOverflowth plugins to the next level by allowing modular deployment with OSGi

Would this be what I am looking for?

Check out the Binary Artifacts plugin, which allows you to create artifacts without distributing the source code. If you create a combination of interfaces, extension points, and documentation then you should be able to let others use and extend your functionality without distributing your code.