I think the company has confused people with the 38 hour rule, because people are thinking that they are going to be flying 38 hours per week! Many of us will be working on the ground for quite a few months, so it is a good thing that I can't be forced to do more than 38 hours, if I am stuck on the Virgin Blue checkin counters!
The 38 hours is one rule, but the flight time limitations are another, which will not permit 38 hours.
Both rules run side by side, and must both be adheared to. Flight time limitations combined with the 9 RDOs will only allow a crew member to do 3.5 SYD-LAX trips in a 28 day roster cycle. BNE-LAX trips will be even longer as they involve paxing to BNE the day before. Therefore the most you could do would be 1 x BNE and 2 x SYD trips, there wouldn't be enough days left in the roster cycle to cover minimum rest and the required 9 RDOs.