Here are some of the larger e-ink displays.[1] No prices given. They're being pitched to cities as bus stop displays, because they can be run from a small solar panel. It might make sense for that, because having power run to a bus stop sign probably costs more than an expensive E-ink panel.

I notice that some Alibaba sellers of similar displays copied some of their images from that site.

[1] https://www.smartcity-displays.com/large-format-e-ink-displa...