Have you thought about contacting the respective embassies of some of the countries in those areas? An embassy can be a wonderful source for travel information, maps, and posters.
You could also try visiting local travel agencies to see if you could get any of their old posters.
Also - try visiting epals.com at [url]http://epals.com/[/url]
If you're lucky, you'll be able to find foreign pen pals!