I'm in the process of writing an MSc dissertation on using Permaculture principles as the framework for a Project Based Learning (PBL) approach in High Schools (Focusing on 9-12 in Israel). So I recommend for space in your curriculum to allow students to choose and develop their own projects, with Permaculture principles as the framework.
By the way, if you have experience with project+permaculture based programs in High schools, I'd love to speak to you about it.
I also think you should include for High schools and/or Middle schools the topics of passive design and Carbon Footprint (the students could do a Life Cycle Analysis (LCA) - Check out Daniel Golman's book 'Ecological Intelligence')
If you want some presentations or papers about PBL, Passive Design or LCA, let me know.
MSc in Theory and Practice of Sustainable Design
Welsh School of Architecture