Sun Tzu, many people treat the Boxer "Rebellion" of 1900 as a colonial conflict, seeing that as an indigenous war against colonizing foreign powers. There is also Chinese conflict in the 1850's and 1860's Taiping War (second bloodiest war in history according to some sources) which triggered British and French invasion in 1860. There is also a war or two between the French and the Chinese over Tonkin in the mid 1880's. The conflicts inside the Chinese Republic after WW1, with some outside intervention by foreign powers such as the gunboat patrols on the Yangtze, were probably being treated as colonial conflicts by miniatures wargamers before the term "Back of Beyond" came into general use and embraced those interwar conflicts.
The key choice is terrain. If you prefer desert and arid lands to model, along with characteristic desert style buildings, then a zone of colonial and BoB conflicts including Afganistan, Central Asia, the Middle East, North Africa, and maybe even Mexico and South Africa can be covered with some of the same terrain pieces. If you prefer woods and Chinese style buildings, then you can merge imperialistic foreign interventions in China with Chinese BoB. It's often more of a challenge to build up a collection of terrain pieces and buildings and find the room to store it all than it is to paint a few figures and store those. So pick the type of terrain you want to collect first.
Fortunately, modern pulp type rules and great individual figures allow a person to start small with a few painted figures and small playing surfaces, while later building up bigger collections of figures and larger playing surfaces for those much bigger battles.