The big hamster version was more available (as I had seen it in shops around seven years ago),
but the small one I found it with the help of a friend of mine in Taiwan (she also helped me to get
a... dozen Taiwanese Octos at the time).
I got six small Hamster/Hamtaros for which five went almost immediately to friend collectors (I kept one).
Since then, I had never seen them on sale or trade by anyone, but if I see one I will let you know!