<i>This method works, but it isn't terribly user friendly to create and
maintain the questions and answers (selecting an AssessmentQuestion and
having to select "AssessmentAnswer" click "Create Here" 5 times is sort of awkward for a non-technical user.</i>
Have you thought about creating an override of the object/edit template in the admin interface to make it easier to add new alternatives when creating/editing a question? Also, you might be able to use the matrix datatype for this purpose.