Thanks again. I have noticed that as well. I just shot them an e-mail. I am crossing fingers for a delivery to Australia.
I will be using the Gaiwan for myself and maybe one guest. In this last case, can I get away with 90mL?
Again, just depends on the size of your cups and how much tea you like to drink at once. To me, 90ml is plenty big for up to 2 or 3 people; if you've got some cups that are around 30-50 ml, you should be good (the tea will take up some volume, but possibly not as much as you think, and you aren't going to fill the cups to the rim).
If Tea Gallery won't ship, you could try http://jingteashop.com/ (based in China).
They have only a limited selection of porcelain on their site, but can generally find other stuff if you contact them directly. Overall, I think the quality of their porcelain is good.
Best Tea House also has some really nice, thin blue and white porcelain gaiwans (you can see some in the pictures I posted in the teaware thread) that are about the right size; they don't have an online shop, but I can put you in touch with folks at the HK or Canada branch if you want to try to order one. The price won't be super cheap - I'd guess around 30 US, give or take.