Wow, I can see you're rolling in enthusiastic replies...
USYD runs a Bachelor of Commerce/Bachelor of IT...... IPT and IT pretty much the same and commerce involves some elements of economics, not a very large perecentage however.
UNSW has a computer engineering/arts programme... they have economics as a major. I'd chose this one because the economics major covers all areas of economics and computer engineering is a booming subject.
HOW did i not know about UTS before?? It looks like an innovative university, i should look into it more.. anyway they have Information Technology/ international studies. You couldn't possibly run international studies without economics in there somewhere.
I know how annoying finding the right course can be, this coming from someone looking for a suitable degree for a Diplomat, so I really hope I helped you out.