I did Mao Zedong based on an interest in communism, so if you wanted a Marxism focus: China, Russia, Cuba, Vietnam...? maybe major personalities or events related to communism in these nations?
don't worry i did extension history this year, it's only two major course sections and a major work so it won't be too much of an extra load. Plus it scales really well if you're ot doing as well in one of your main subjects! So glad i didn't drop it, because i know it'll be counted instead of...