Oh wow what a compliment coming from you!!! I really appreciate you taking the time to have a look through my gallery. I am hoping to partisipate in your workshop... could you let me know where about's in Sydney we will be working... so i can look into accommodation etc.
The 10 stop filters are usually a special order, but if you go to a GOOD camera shop that sells pro gear, they can usually get it from their wholesaler. There's not many of them around, the one I got is called a B&W 10 stop screw in filter.
Let me know if you have no luck sourcing one and I'll find a link to an online store for you.