Qantas currently have Melbourne, Sydney or Brisbane to Noumea return for $448 economy / $998 business class as part of their "Fly Away Sale". Flight availability is from mid July all the way through to next May. Melbourne departures transit through Sydney, with both Qantas and AirCalin making the flight to Noumea.
IMO, the business return fare ex Melbourne is the real kicker, and there is good availability for peak times like Easter 2017. Ironically, it's more expensive to fly one way in business class from MEL to SYD than flying one way MEL-SYD-NOU!
Flying MEL-SYD-NOU return in business will net you 200 status credits, which is a significant haul for the cost outlay (and one of the best I've seen for a long while) - just be sure to make sure your flights all hold a QF number in order to ensure they are eligible for SC (and points) earn.
Note that these fares are available through the AMEX travel portal - https://travel.americanexpress.com.au/travel/arc.cfm - and booking the economy return fare would be a great way to use the $300 travel bonus that comes with the AMEX Platinum Charge card (per deal: https://www.ozbargain.com.au/node/236605). Please consider using my referral link at the bottom of the AMEX referral wiki under 'Platinum Charge Card' (https://www.ozbargain.com.au/wiki/american_express_referrals) if you're interested in signing up.
Alternatively, if you were quick enough to take advantage of the AMEX $50 cashback on $350 Qantas spend deal (per: https://www.ozbargain.com.au/node/251632) you could consider paying via Qantas online with your AMEX card (noting that a decent chunk of the cashback will be eaten up with credit card fees).
Whatever you choose to do, move quickly, as this sale ends 24th June.
Great write up.
The first thing I thought of when I saw that business class pricing was status credits (aka "Mileage Run Deal")
Forgot about the AMEX credit, and the Platinum Charge $300 travel bonus too, but that's an awesome reminder.