Is there an e-ink reader with a 8.5"x11"/A4 screen that'll display PDFs? All I want is to be able to bring all my tech ebooks with me to work and be able to look things up/brush up on things on the commute/flight etc.
Sadly, being a hardware company is tough and the product line became unprofitable. The android version ended at 2.3, but it was sufficient to put on several readers. If your books were in a standard format, the built in reader worked fine. There was also community effort to either mirror the screens or force other reader apps onto the e-ink panel.
https://pro.sony.com/bbsc/ssr/show-digitalpaper/resource.sol...
[1] https://github.com/koreader/koreader
[2] https://github.com/kai771/kindlepdfviewer/tree/librerator
I sold my DX (the "current" gen) and bought a 3rd Gen iPad the minute the retina display was released. I still pine for the eInk display though. I've half considered a hobby hack project that involves a Kindle DX brain transplant.
I have one, and use it for good purpose with a variety of text books. The ability (or constraint?) to not be distracted by colourful networky things is grossly underestimated, but even more so is the ability to stare at the thing for several hours, in a variety of lighting conditions, and not feel any type of eye-strain.
Horribly expensive at the time it came out, and probably rare as rocking horse poo now. Looking at the other responses to your question there is slim pickings for contemporary devices with these specs, sadly.
I have an old Kindle 3G that I use for reading papers. Its screen is 4.8" in height, which is just about the default column width of LaTeX (= 8.5" - 3.75" margin = 4.75"), meaning I could comfortably read papers in landscape with only scrolling up & down.
PDF reading was okay. It was rather slow, and you couldn't highlight/markup anything, but the rendering was gorgeous.