Cheap flights to Melbourne return, Tigerair announces daily route
obviously the timings won't be attractive to anyone except leisure & small business traveller who pays own fares.
Hundreds of school want to go to CBR every week for 4 nights Mon-Fri, but many find the fares too high & don't go & flying in & out of SYD is not that cheap when add in time for bus transfers SYD/CBR/SYD.
CBR/BNE could also work.