I think a lot of the South American postal services are rated as one of the worst for theft and loss of items. They probably also have really strict border controls, but if you can get past those issues this is quite an interesting idea. I think a lot of people have similar collections (I've seen people with each note as they went down in value even more - eg starting at 10 Bolivar to 10 billion Bolivar or whatever the "equivelant" bank note is now. It'd be really interesting if you could find someone with a set of those with similar years on them too...