I am off on an "Asia Explorer" ticket this weekend SYD-HKG-TPE-HKG-SIN-CGK-SYD which, I believe, is a D class bucket. I think it's just the discount version of J. For me, this fare was a lot less than an equivalent J.

Downside is that QF seems pretty stingy with D inventory and I am CX on the SYD-HKG leg and I would have preferred QF (for the bonus points!).

Booking was through a normal TA.

QF fare details are available here