Where can I trade gold versus Australian dollar future ?

I'm sure there are some CFD and/or Forex shops that offer it as product, alternatively you could trade PMGOLD which appears to be an Australian/ASX Physical Gold ETF that trades in AUD not USD on ASX.

Lastly you could create a synthetic by using both the CME Gold and USD/AUD futures.
- GC is the CME/COMEX 100oz gold future so at $1890 thats $189,000 notional
- MGC is the CME/COMEX 10oz 'micro' gold future so at $1890 thats $18,900 notional
- 6A is the CME AUD/USD future with a notional of AUD 100,000 so at 0.72 that's US$72,000
- M6A is the CME AUD/USD 'micro' future with a notional of AUD 10,000 so at 0.72 that's US$7,2000
So 5 MGC plus 13 M6A is a well hedge $94,000 Gold Position in AUD. (3 plus 8 is also pretty close. Problem with 1 plus 2 is that your 31% underhedged on the currency and 1 plus 3 is 12.5% overhedged). Still the currency is a lot less volatile than the gold.

Never heard of a single contract for that. You could trade a spread in both markets though.