CI already has x86_64 builds supported but they are not tested and not directly usable from CI in terms of packaging. The online installer could optionally have support for x86_64 for QNX 7.1 later on as now customers are anyway building their own toolchains. Also RTA testing should be done.
The general agreement has been to only support one platform per OS while PS would take care of the remaining combinations. However for this case there have been customer requests meriting a further consideration. QNX is currently a well selling RTOS.