Update: May 2023
In the intervening 8 years since my original answer I eventually did purchase a Remarkable 2, which is a larger format note taking device that also functions as a capable e-reader (though it does have drawbacks like a lack of compatibility with Amazon Kindle books - you can workaround this, but it is annoying). I used to recommend this device without reservation, but it is somewhat dated now in terms of tech, and they have added what amounts to a mandatory subscription for basic syncing functionality etc. (as an early purchaser I get to keep the functionality without a sub).
In terms of current options, if I did not still own the Remarkable 2, I would be looking at the Kindle Scribe, or the Boox Tab Ultra C which even has colour (at a lower PPI).
Original Answer
I have not pulled the trigger on this purchase, (because of the relatively high price), so this is not a hands-on recommendation. When I went looking for an e-reader for reviewing and consuming technical information, I was most tempted by the Icarus Excel.
It is a 9.7" reader and allows for handwritten notes too. Since I was evaluating for technical learning, this was a big plus. The Icarus site is not great, but there is a good review, with video, here.
I don't think the market for these larger format readers is particularly mature, and color e-ink may yet disrupt the entire market (small format included). If the larger format is a must have, and money is not an issue, then the Excel looks like a good option right now.