Try Airservices Australia
www.airservices.gov.au/. The Airport Services division employs controllers with only tower endorsements everywhere from Alice Springs to Sydney. They also manage US VFR Towers in Hawaiii and Guam but I think you need an FAA licence to work there. (For those that are wondering Approach Control is part of the Air Traffic Management empire and will eventually be manged nationwide from the two Centres in Melbourne and Brisbane.)