Self-Sufficiency?
If you Google "cuba food imports" you'll learn something interesting: Cuba plans to import 1.9 billion dollars worth of food from the US in 2008 alone.
They haven't survived peak oil -- at least not yet. The island's population is still too large for the amount of food they're able to produce. Which means if their money runs out, or something changes in the US, they've still got a lot of pain to face.
So, it's a bit premature to use them as a guideline on "sustainable" living, don't you think?