Dr. Gunson recommended Julio Cifuentes to me as the only surgeon (he knows of) in South America he'd trust with a revision like mine (for the most part). He's from Chile, and when I called in his secretary estimated the cost of surgery at 22 milion chilean pesos (29k in US dollars). That includes hospital, anesthesia, plates and screws, fees, etc.
For reference, if I were to get the surgery Dr. Gunson suggests, it'd be a 5-6 mm anterior downgraft, 8 mm posterior downgraft, that presents added difficulties because it's a second time intervention, my orthodontic set-up is (very) bad and I have little bone on one side of my maxilla.
Let me clarify though, he can't guarantee anything with a referral and still said it'd be convenient I go to Santa Barbara. Another thing to note, he said many surgeons can execute first time surgeries well but that revisions are sort of another category. So if you're going into it fresh, it'll probably be easier to find someone suitable.