We are doing a study on decision making in health that accounts for political economy. Our model actually goes back to the original paper by Anthony Downs http://www.hec.unil.ch/ocadot/ECOPOdocs/cadot2.pdf. There is also a book by Downs with the same name.
Other really interesting ideas are in the work of Bruce Bueno de Mesquita, Douglas North and Barry Weingast.
This is a very interesting question. It is also one of my own areas of research. For a very insightful political economy perspective of governance -- with a specific emphasis on education reform -- the 2004 work of Prof. Merille Grindle is a must read:
Grindle, M. (2004). Despite the Odds: The Contentious Politics of Education Reform. New Jersey: Princeton University Press.