Hmmmm..... Based on my previous searches there really is not much available. Occasionally a classic is listed on Ebay but they seem to be few and far between and they fetch some hefty/rude prices.
There is a crusty bloke out at Penrith that has some junkers that would suit a MAME project but you will be lucky to get anything classic or for that matter, anything in great condition.
He might be worth a try if you are willing to put in some hard restoration work. I have been there a few times and there is always
something.......
http://www.kfe.com.au