Give us a better idea of what your resources are. This is your Masters. What was your Bachelors in? What knowledge do you have so far that can be applied to your thesis? When you say sustainable development, what aspect are you focused on? Garden? Buildings? Transportation? Irrigation? Waste? Where are you? What's your local environment like? wet/dry? grassland/forest? hot/cold?
You've ruled out economics for good reason. I'm assuming you rule out regulatory issues for similar reasons, although there's a lot to be done to repeal zoning restrictions in many places. You could look at the regulatory landscape and how it effects permaculturists: water harvesting, greywater, livestock in town, mown lawn ordinances...
I see a lot of people asking "How do I make the transition?" They mulch kill their lawn and try to convert it to a permaculture garden. You could look at methods for this transition. Compare heavy mulch with grazing a pig, or a dozen rabbits in a moderate area. Compare buying in straw with owning a paper shredder. Compare permaculture systems that use livestock to those that don't.
Audit your community for resources. Look at potential nutrient sources, fuels, fuel needs, land (both vacant and underused), water, etc, and build a new model of how that community could function under permaculture principles.
Find an intentional community committed to permaculture and document their efforts. Consider what's needed on a community level and what physical and sociological challenges must be met.
The book The Integral Urban House was written 35 years ago. Write an update.
Run a survey to establish what the standard skill set and physical tool set of the successful permaculturist is. Describe it in terms of what a B.S. in Permiculture would have as a curriculum. Or do the same, but imagine it not as a B.S., but as a course similar to, or building on, Master Gardener programs.
Produce a series of model plots, each incorporating different soils, hydrology, exposures, and human populations, and produce a permaculture design appropriate for each. This is somewhat of a landscape architecture approach.
Still thinking...
Dan