Does anyone have any more out there?

A few that would be reasonably well recognized within Australia, but probably not outside it(?) are:

Sydney - The Harbour City
Adelaide - The City of Churches
Alice Springs - The Alice
Broken Hill, New South Wales - The Silver City (probably one of several around the world)

More universally perhaps (but not in Australia!):

Motown
Tinseltown (although I guess strictly it's just referring to one part of a larger city, and the predominant industry therein)