The link, and indeed the whole blog, is worth reading. However, it doesn't directly answer the question. Bunnie suggests dealing with Chinese brokers who can source availability of 'cut tape', remnants from large production runs of the chip. It doesn't address consistency and reliable supply issues over a longer period of time but does allow for procurement of relatively small quantities of parts.

Bunnie also suggests learning enough Chinese to participate in what he terms the "gongkai" (公开), the quasi-open but legally murky design and production ecosystem producing much of our electronics, where documentation and specs are apparently available about as freely as torrented episodes of Game of Thrones.