With the great help of azkedar I managed to regenerate new, mint, island-in-the-sky lookalike skylands lots! And it seems that this is a method that is supported by the very internals of bukkit, so it’s to stay around!
All that is left to do regenerate some 50-70 lots in the skylands…. which will take some time. But at least it works now. Thanks Azkedar!