Magpies around Brisbane might like to try Reverse Garbage, a nonprofit group run by Friends of the Earth. They collect industrial discards and sell them out of a small shed on the corner of Ashington and Montague Rd, West End. (note: I'm not connected with them, just a very big fan)
This is a truly fantastic place. Small plastic discs, fabric samples, electronic bits, scrap cardboard, plaster teeth & feet casts, vinyl, tiles, pots ... everything! When Scooby Doo the movie was shot on the Gold Coast, the set designer was a regular visitor to Reverse Garbage for bits and ideas.
I often have to avoid the place because I know there's a lot of stuff there I'd take home, and I haven't done anything with the last lot yet!
I've heard rumours of a similar place in Melbourne, but have no details.
Kfish