There's also the MobiScribe Wave (https://mobiscribe.com/), a color e-ink Android tablet, with frontlighting, and excellent battery life. On standby, it lasts for weeks. I have it hooked up to my Bluetooth keyboard. It runs emacs, a web browser, and email client - plus all the usual e-reader apps.

(Yes, I'm aware there are several other Android e-readers. The Wave has the unique combination of top-end handwriting functionality with waterproofing.)

I think the closest thing I've gotten to the Linux + E-Ink dream(for me at least) is the Pinenote with a bluetooth keyboard. It's been a surprisingly enjoyable portable device(nice wireless keyboard doesn't hurt either) and it's powerful enough to do some nice simple stuff, then disconnect they keyboard and it's back to being an book/newsfeed reader.

Oh, the Clockwork Pi is also interesting.

https://www.clockworkpi.com/

The irony of a retro computer with a web page that is unusable(can't click, scroll weird, ...) because too modern webdev :)