They were a special edition. The one in my avatar is one <--. I just put orange caps on it. They actually aren't that rare, there are a bazillion of them on TaoBao.cn, but getting them is another story. I don't believe they are made anymore, because now the only white ducky is that year of the rabbit edition (full size). There must be more out there, though. And 'Special edition' in keyboard terms just means that they stop making them for a few months and bring them back.
May I ask what you particular interest is? If you just want a white board with blue switches, there are a few options, but this one is not one of them. Off the top of my head, the PLU-87, Filco, Leopold. I feel your pain though, if its that WHITE white color that you're after.