I think I could get by on $30,000 a year and working on my own ISV in a nice Latin American country. Is anyone doing that here?
About $35000 here in Thailand gives me a lifestyle that I think of as lavish and decadent, but I guess the OP would consider frugal and cautious. 120sqm condo beside the sea, eat out every night, tennis and language lessons. I could probably cut the budget down to around $20000 in a pinch and still live comfortably. The major downside is that there aren't many hackers about.
Whereas Costa Rica lets you stay for 3 months before you need to cross the border to extend your visitor visa. And apparently obtaining a permanent residency isn't difficult if you can prove income from foreign sources.