I called QF today who mentioned that should I organise even a 20 segment xONEx, I should be able to get an e-ticket assuming of course all the oneworld carriers in question have e-ticket interlining in place. Thought it was worth letting you all know although not sure of course if this will happen in practice.

I plan to book a BA/QF/CX/AA ticket shortly ex CAI and will report if I am able to get an e-ticket.