I understand that the plan is to complete all blocks that have a shell already and not to build those that don't - someone correct me if that's wrong.
Therefore my counting makes that
6 more blocks including 271
32 apartments per block (I think La Isla is the same as the penthouses for number of apartments per block.
So that's 192 left to build. In terms of how many left to sell though that's much more as there are a lot of empty or bank owned properties.