Snesguy, chance of finding anything truly deemed rare in Australia in the wild are pretty minimal. Your only real chances of finding anything rare on the consoles you have mentioned are the following games:
Mega Man Wily Wars - Megadrive
Daze before Christmas - MD/SNES
Uforia - NES (debatable if this is rare or not but gets some good $$$)
Terrinigma - SNES (same as uforia)
And pretty much the other titles already mentioned but I will say in all of my years of hunting I have not came across nearly all the games mentioned in this thread in the wild and its even worse now with everyone thinking any classic game is worth 2k monies on eBay.