Have a look at this 6.4 inch smartphone:
https://www.engadget.com/2016/05/10/...ax-smartphone/
and at this 6.6 inch smartphone
https://www.engadget.com/2016/08/01/honor-note-8/
with this size I would not mind a dual screen ips/amoled and e-ink smartphone, developed and made in china
well, it is bigger than any yotaphone and so it is comfortable for reading.
the first smartphone is around $200-$250.
If the front camera is removed, the e-ink 6 inch carta 2 display is added, it will not make the price much higher.