More Words, Deeper Hole

Smallish islands also seem to be particularly bad at comparative advantage in many cases. All the scattered islands of the Pacific spring to mind. Imports of everything to a small market make it expensive to live there and almost nothing they export is unique enough to command prices equal to the cost of shipping it off. Tourism does work to some extent for those island nations that get the air links, but it seems there are just as many that remain backwaters because their beaches are not pretty enough or something.

Some sparsely inhabited parts of the US, the bits being depopulated due to farm/ranch abandonment, are also probably examples of not having a comparative advantage. They cannot produce anything agriculturally less expensive than other places in the US and they don't have any other resources like minerals or a scenery that makes people want to movie their corporate headquarters there.