I shouldn't just say that I'm looking for a tablet for e-book reading. What I should say is that I'm looking for a tablet to read full-page-at-a-time textbooks and 8.x5x11 pdf journal articles.
This might become a possibility soon: for PDFs, combining the forthcoming ASUS Chromebook Flip
with Notable PDF Viewer and Annotation App
to read in tablet mode. For ebooks there is Play Books or Kindle Cloud Reader (and possibly others).
The advantages of this option would be that one could quickly switch between reading and annotating mode by simply unfolding the device and using the keyboard. And with Notable PDF the notes would be instantly synced across devices and platforms.
And it would be a multi-purpose device (tablet alternative), as it is of course a fully functional Chromebook.
The downside is that in Notable PDF you can't (yet?) change the colour scheme for the background and the fonts (although the brightness can be controlled via the Chromebook).
But with Play Books (as it is run in the Chrome browser) it is possible to use some dark or night styles with the Stylish for Chrome
extension, as a workaround to make it easier on the eyes.
P.S. I also just realised today that in Play Books it's possible to select viewing the scanned version of the ebook, thus having a PDF-like experience, and seeing the actual page numbers, which are important in some cases (such as academic work).