They turn blue when pounded, but not when transferred. A close friend of mine bought an ice bori and it's sitting safely on his account, still ice. I've also seen another two for sale, but both of them were compromised by the sellers being stupid
There's also quite a few in the PC trading stream right now.
You can make them if you downloaded the toolbar back in '04, but not everyone made one. There's still a few people who haven't made theirs, and the ability to make an ice bori stays forever if you didn't. Only one creatable per account, though.