In QLD Co-owners are assessed separately
http://www.austlii.edu.au/au/legis/qld/consol_act/lta201090/s22.html
Trust land assessed separately
http://www.austlii.edu.au/au/legis/qld/consol_act/lta201090/s20.html
Most tax agents wouldn't take on land tax issues - so check to seek if they can advise on this first. I just had a client who suffered a $4000 loss by incorrect advice from a tax agent.