Is volume manufacture coming?
Email from RPi Foundation
At the moment the Zero is limited to one per customer. At present we are focusing on getting the Zero into the hands of individuals and will not be offering a wholesale option in the near future. For industrial purposes we recommend the A+.
April 2016 update
Raspberry PI Zero production is restarting in Wales next Monday after a hiatus to allow us to focus on Raspberry Pi 3 (a million units built and counting). We have placed 250ku of new orders, and are aiming to produce at least 50ku/month for the rest of this year. Distribution will continue to be via Pimoroni, Pi Hut, Adafruit and Micro Center for now
March 2016 update
Fortunately, there’s light at the end of the tunnel: production is being ramped up to meet demand. “I placed another 150,000 POs [production orders] – well, a pair of POs, a 50K and a 100K – in the last couple of days,” Raspberry Pi Foundation co-founder Eben Upton explained during an interview in early February. “It’d be good to get to a point where we’re doing at least 50,000 a month for Zero. I think we could do 50,000 a month on Zero pretty comfortably.”
Why is the zero not available from RS and Farnell
The RPi zero is being manufactured by the foundation themselves, not under license by distributors, and the profit margins are likely much tighter than on the full spec products. It may be that there is not enough margin for these catalogue distributors to be able to stock them and make the margins they need to operate.