Fantastic price on Royal Brunei to Vietnam.
Airline: Royal Brunei
Stopover: Bandar Seri Begawan
From: MEL
To: Ho Chi Minh City
Dates: Feb-April
Skytrax rating: 3*
Lots of dates from Feb/Mar
Check out the various dates on FlightScout, and then also search on Beat That Flight as some dates are cheaper, eg $415 at the end of February.