I see them on USA ebay all the time but the sellers want over the top prices for banged up examples. So if your paying $200 USD plus post of $80 USD to get it here, then paying someone $500 AU to make it look new again for you (remove dents and paint), it ends up being pretty pricey. People will happily budget $500 for paint and $500 for chrome to do an old road bike tank but i cant see many wanting to spend a lot on a RM tank on a race bike unless its for concourse resto. You may want to look at getting a new Clarke plastic replica one if its not important to have the original alloy one.