Sure would be nice if they could carry this through to the "regular" non-QBR booking engine, AND also have the booking class indicated in the e-ticket (not just shown only during the booking process).
From the FAQs:
Is my trip eligible?
Your trip is eligible to request an upgrade if:
Your flight is operated by Qantas
You bought an eligible fare. Most fares are eligible, but Qantas does not allow upgrades on “Sale” fare classes for international flights.
Your trip can be booked anywhere...
I managed to pick up a very good (for Qantas) sale fare from SYD-SIN in business over Christmas returning in the new year late this afternoon. Had been watching the fare for a few days now and had fully expected it to disappear with this promotion but it held.