Sweet, sweet success!
I made a ~30 minute phone call about 45.5 hours after the last phone call (I doubted whether I would receive a phone call within 48 hours for some reason).
Sony were great (couldn't quite make out the name of the person who spoke to me..) - he gave me a work order number and instructions on where to send my Reader in the US (Laredo, Texas, near the Mexico border) - all I need to do is pay the shipping there from Australia!
Thanks Sony!
Now all I need to do is find the moral fortitude to entrust my Reader to the postman..
Let this be a lesson to all the naysayers out there who said people outside the US can't get their firmware updated by Sony USA!
On to Round 4