Looks like the Z1R is back in stock at Audio46, so it seems that it's still in production and shipping out to dealers. I had heard from a different dealer the rumor that a previous shipment last year was going to be the last one, but it seems that's not the case. And CES has come and gone without an announcement of a successor, so the Z1R will probably remain Sony's flagship headphone for at least another year.
Good to hear. I wonder what their sales strategy is. It's been out of stock (except for one store in Austria! which is apparently the only one that can still order it from Sony) in the EU for about a year or more. Why do that in such a huge market if you're still producing the unit. Baffling.