Davey,
have a read of
http://www.rex.com.au/cadetpilot/cadet_faq.pdf it will outline the conditions, as well as including a link to the award, from memory it's in the 30k mark...
Also keep in mind that the hours will be logged as ICUS (In Command Under Supervision) which is worth bugger all to most airlines as they want Command time.
Just noticed that you are from Ballarat, Sharp Aviation in Hamilton have a cadetship as well (going for around 96k from memory) and from what I have heard is quite a good cadetship, however your still paying an airline to give you a job and in todays job market that isn't something you need to do.
There are so many low hour jobs going at the moment (check out AFAP), so after say 18-24 months of slogging around in SEP's and probably getting a few hundred hours of MEP (COMMAND) time you'll be in a favorable position to get a look-in to most airlines.
The airlines have orders flowing in, so the market shouldn't dry up any time soon, so being locked in to a regional which is hemorrhaging pilots for 5-7 years sounds almost pointless... You can quite easily enter a regional such as REX with the above mentioned experience and bail out whenever you wish, without having to worry about what you and your family are going to do about this 80k plus 10% interest loan.
I too have considered these cadetships, but have decided to do it on my own back.
Once you have a CPL you can still apply for a Qantas cadetship, so your not locking yourself out of the possibility, plus a CPL will show them you are keen on a career in aviation!