Edit: if you're curious, look into the likebook mimas as a starting point. There are other options, that just happens to be the one I've used.
I'm aware of the new breed of large readers but haven't been able to try any, and I'm concerned they won't be powerful or sturdy enough compared to the fragile, sloooow DX to justify the outlay. I don't have much use for notes.
I realise the DX is a dinosaur though compared to the new ones you are talking about, and would love to be pleasantly surprised by a quantum leap...
...I find it a bit amusing that its model forms an emoticon that fits your general sense of the device.
Unlikely to happen: similar to silicon, eink's yield (that is, amount of parts produced with no errors) goes down quickly (quadratic if not cubic, I forgot) with increasing size.
A system based on lots of eink chiplets with small enough margins that you can tile them could scale up, but the margins are also a difficult area.
*ie classic Kindle with e-ink or similar, not a tablet like iPad/Android equivalent or the annoyingly named Amazon "Kindle" Fire etc.
Not great for tech manuals, admittedly