There are no Australian versions of ZWave or Insteon, and no sign there ever will be at this stage. The European and UK versions of ZWave will work in Australia, although any power sockets will have to have convertors of course... the only issue is the RF frequency used in EU/UK is a little different from that registered in Australia for the same use... so using it would technically be illegal. I have investigated that band, and it appears not to be used in Australia at the moment and the range of the ZWave signal is comparitively, very small.
X10 is pretty crap, and the prices Bunnings charge are criminal for 30 year old technology. PLCBus is working, available, and somewhat better than X10 but is still very slow and unidirectional, so unreliable.