Yes, I did QF81 a couple of time (around 2003-5) from ADL-DRW, was a nice use of upgrade credits (remember those?) on a domestic sector, IIRC on skybeds (MKI) when they were quite a novelty and shiny and new. Also started a DCIRC using QF81 from DRW-SIN, after needing to be in KNX for work once.
If you go back far enough, QF did operate CNS-DRW-SIN before they turned it over to Australian Airlines, as QF61/62 (I think). In my flight database I can see that in 1994, in one of my earliest business trips, I took QF62 from DRW-CNS before transferring to a purely domestic flight to SYD. I'm fairly confident that the flight originated in SIN.