Yeah, me too. They stopped displaying them suspiciously close to the end of the year. I suspect that rather than sell out, they either sold all remaining stock to a reseller or just recycled them. The latter would be a tragedy, but they may figure they've sold all that it's worth selling at below cost prices. It might be worth emailing them just to make certain.
On the flip side, while I regret not stocking up on them, what was I really going to use one for? Do I really need a NuBus machine to run faster than about 100MHz? If so, in this day and age, why not just use a PCI Mac?
It's kind of like putting a Turbo601 in your IIci now days. What's the point when you can pick up a 6100 or 7100 for next to nothing -- or could?