No, they are not. At the moment you can only buy one if you are a registered developer and are willing to sign an NDA.
Not even that. They held a lottery for registered developers and gave the winning developers a developer kit. As a registered developer who was not selected for the lottery, I cannot even buy an early-access unit.
iFixIt signed up for that lottery and was picked to receive a developer kit. I remember when I signed up for the same kit, I did a very cursory skimming of the NDA and it was pretty explicitly stated that I wasn't allowed to publicly publish pictures or even publicly discuss the unit/software.