Our back and forth inspired me to add a new post to my blog providing more background on the effort to create an undergraduate minor and a graduate certificate program in Environment and Sustainability. (http://theconsensusbuildingapproach.blogspot.com)
We are trying to distinguish the Energy Minor and the Environment and Sustainability Minor. The less they overlap, the better (in terms of getting them both adopted by the faculty).
I agree completely with your point about the need to offer relevant classes in each student's major. That's why we have adopted the idea of sub-specialties. But, we can only offer sub-specialties in areas where departments agree to offer the same courses on a regular basis. We have not gotten any indication from Course VI that they are willing to offer a sub-specialty. We are working with Chemistry to develop a Green Chemistry sub-specialty.
I like your IAP suggestion a lot!