Carlos
G'day mate.
Take a drive or ring around the orchards up Gatton way on the way to Toowoomba. There are a fair few Apple orchards there. Ask them for some prunings or some of an old tree they are taking out. Tell them what it is for and it should cost you nothing. I got some from an orchard in Bachuss Marsh (VIC) on a drive through there about a year ago. Apple is pretty mild. Try some Melaluka (Ti Tree) it's a bit like Hickory, Try some red gum it is distinctive but has no eucalypt taste.
When you try new woods make sure they are dry and are hardwoods, just use a little. Too much will give you a bitter taste.
Regards