Hi Needy,
I reckon I could sell 5 mokes a week - if I could find them! I often get stopped and asked where to get one.
They don't come up on eBay much here, and all the ones on carsales seem overpriced. I think the Quokka is your best bet, look under 'vintage and classic'. Online is better - the paper version is a nightmare to find anything, and costs $2.
If you are really desperate, don't discount importing one. There are more to choose from over East, and generally cheaper which helps with the transport. Just a bit hard to inspect!
Cheers, Maddog.