Although the idea of a mixed wargame army of 1/600 fighter jets and helicopters along with 6mm ground forces sounds intriguing. If you've not seen the 1/600 aircraft go take a look at picoarmor.com.
I can fit out the infantry with my current 6mm models and several of the fighting vehicles. I can almost say the same for my 1/600 collection. I will put together some sample pictures of an all 1/600 Ejercito Ecuador force and an mixed scale force of 6mm ground with 1/600 air support to post here later.
Also on the general conflagration between Latin American states I don't think including the big three of Brasil, Argentina and Chile would work unless you divide them up against one another. Perhaps more in the North. Anyway Cenepa War for certain and perhaps just a general war between Peru and Ecuador to keep it simple.