Boeing can do it and both manufacturers have submitted their proposals to Qantas. The next issue is to get regulatory (CASA) and union (EA) endorsement to enable duties excess of 20 hours, which requires studies to be undertaken on fatigue and other factors etc. Qantas will not be able to progress ULH without current duty extensions. For example - for Singapore Airlines SIN / US sector; the flight requires two Captains and two First Officers rostered for the duty (rule required by the regulator).
Qantas will be in a position to place an order for delivery by 2022, once this gate is passed (if it does).