For a single return to earn 360 SC's you will need to book a flight that is 7,001-8,400 miles in business.
MEL-DXB is 7231 miles
MEL-LAX is 7921 miles
Both would earn 180 SC's each way in business.
Both destinations are around $8800 return.
A possibly cheaper option would be several nested business flights. MEL-SYD-CBR return with CBR-SYD-PER return nested for example. I haven't done a SC count or cost for these.