Also really top devs (at least in Brazil) can make more than 50k USD per year (fluctuates widely based on exchange rates) at Brazilian companies, it is cheaper than US but the tail-end of talent can still be expensive.
If you really want to attract good devs in cheaper areas the best way is to just open a branch of your office there, pay top-salary and don't just use it a dump ground for the projects no one at home wants to take. So treat them the same as at home. I had a roommate who worked in one of those companies that take offshoring projects, lets just say it is not the best talent pool and the good devs there leave fast.