If I understand correctly there's no need for this discussion anymore. Any oneworld product, in any currency, starting anywhere in the world can now be purchased from any oneworld carrier anywhere. The fare will simply be converted to the issuing location's currency and charged to any international credit card. It's as if the whole world became one big 'Canadian exception'. The restriction that the first segment segment carrier must issue the ticket (or vice versa) also seems to have disappeared. At least that seems to be the situation at the moment.