I'd definitely recommend using a distribution module in your project hierarchy...just another module in the project directory, which depends on everything you want to bundle together. Using <dependencySets/> in the assembly plugin is MUCH less quirky than using <moduleSets/>.

If you'd like an example, check out Maven itself:

http://svn.apache.org/repos/asf/maven/maven-2/tags/maven-2.2.1/

-john