There are e-ink devices that run FBReader.
A few of those need rooting - usually the ones that are based on Android. Please note that there are Android based e-ink devices that have google play store or at least can use side-loaded apk without rooting.
At least one e-ink device manufacturer - PocketBook - provides FBReader as the main reading app. It also supports installation of third-party apps, including Coolreader. PocketBook can use any font you copy to device with fine-grained settings of size, margins, line-spacing, justification, content of the status line. It also supports large number of other configuration options, "screensavers" (pictures displayed then the device is switched off), user dictionaries (the manufacturer provides [unofficial] windows application for generating dictionaries), third-party apps (the manufacturer provides [unofficial] SDK) so you even have a linux console of full-blown Vim [on older version of firmware]. No hacking or rooting needed to make changes.
The most recent generation of firmware is screwed-up compared with the legendary firmware from two generations of PocketBook devices ago. But even this slightly screwed-up firmware 5.xy is vastly more configurable than other main-stream devices, such as Kindle, Kobo, Nook ...
PocketBook is the most popular device that is sold in brick-and-mortar stores here in Europe. Nobody except Amazon high ranking executives knows how many Kindles they sell here.
If you are stuck with Kindle or other device, you can always liberate the DRM-ed content, just search for apprentice Alf. From this liberated e-book you can generate pdf file with page-size of your e-ink display and any fancy typographical formatting you wish.