If you can'tfind modules you can always try the real world for inspiration. Read about the Wars of the Roses, Italian city states & principalities back in Macheivelli's day, Feudal England, Japan, China, etc. Modern conspiracy theories might be adapted to your campaign world (think Kennedy assasination, with your friend's Lord character discovering a plot to kill the King, or maybe trying to find our who dunnit afterwards.)
Another possible source of inspiration is Science Fiction/fantasy. For example you might be able to transpose the situation in Dune, G.R.R. Martin's Song of Ice and Fire series, or other politically oriented tales into your campaign world, changing the territory, titles, and resources being fought over as necessary.