I think they are only selling the 16Gb ones as brand new so as not to compete with the more recent versions, as 16Gb won't hold too big a music/film store etc!

When they came out in 2011 they came in 16, 32 and 64Gb flavours.

I was just pointing out that they are available, and the Amazon unit I linked to is still a new unit (not a refurb). Even a direct refurb from Apple comes with such good warranty that they they are "as new" as you are going to get for a 2011 product.