(Farnell normally allows you to order stuff as "backordered", but for stuff like "raspberry pi" the enormous amounts of backordered items would bog down their system that they don't do that anymore. I think that's the reason they removed it from their site for now.)
Similarly, the pi hut (where I got mine) says "sold out" and does not take backorders.
I remember when the original B first came out. There were hundreds of thousand people trying to order the first day. That was in February. I finally got mine in late June. Other waited months longer than that. And the logistics were a total mess.
At this point in time, I think the quickest way to acquire a Pi Zero is to hangout at the local Barnes & Noble or MicroCenter. The December issue of The MagPi Magazine is due to arrive in the next week or two (I've been annoying the counter people at B&N again.)
