Comet 4s were operated to Sydney via Darwin and I think on to Auckland by BOAC in the 60s. I well remember working on them as an apprentice. I learnt quickly to aviod them if possible because the apprentice job was to hang upside down disconnecting things from the top of a wing when an engine change was required.
At one stage (I suspect prior to the arrival of the B707 138) Qantas wet leased at least one Comet. There is or used to be a B&W photo of it in the Qantas training school.
The interesting thing about this thread is that I suggested the WA story was about a proposal to use ex Mexicana Comets and if memory serves me right, the Seattle one is also ex Mexicana.