AICE has recently updated it's history syllabi. For the United States administered tests they have separated out the subjects. 

• US History to 1877 (8101) AS Level
• US History since 1877 (8102) AS Level
• European History (9981) AS and A Level
• International History (9982) AS and A Level

FL alone has over 150 schools offering AICE courses and AICE estimates it has over 270,000 students world wide. 

There is overlap with World and US History courses meaning some of the information and lessons you already provide could be utilized and the entire course would not need to be created from scratch. There are some topics, however, that are not currently adequately addressed, such as the Russian Revolution and Stalin (in the European syllabus).