Pervasive Displays is a company that designs and builds E-ink screens for the DIY and custom market. They make screens in a variety of sizes ranging from under 1" to over 7", and they just announced a new Spectra E-ink screen unit measuring 12.2" across.
According to the press release, "The energy efficient, multi-colored display is a good fit for retail ESL (electronic shelf labeling), Point of Sale, office automation, and healthcare market applications".
The new screen has a resolution of 960 x 768, or about 103 PPI. It can support combinations of black, white, and red, but not the 16 shades of gray we are used to in Kindle screens.
If the above graphic is real (and not photoshopped) then one of these screens can display 6 colors (black, white, and red, and pink, dark red, and gray). The earliest Spectra screens could show exactly 3 colors when launched in 2013, so if this screen can do more then it would mean E-ink has improved the tech a lot in the last 5 years.
The new screen unit is listed on the Pervasive Displays website, but there is no link to a site where you can buy one nor do we know the price.