Just as a data point, I managed to get onto the call centre with US Dividend Miles and asked - out of pure investigative interest - to book a BNE/SIN J return for 1 pax in May 2014.
The agent said there's plenty of Y available (I think we all knew that), but when checking for J, she checked about 3 months worth of dates and there was nothing. In both directions.
Now most of us who live in BNE who are in this game know what SQ J availability is like, even in (or rather, especially in) May. And we all know that the aliens haven't suddenly invaded.
This is not a good sign....