[Studio717]

Two interim solutions that have worked (somewhat) for me:

I have used an old Fujitsu tablet that I bought off ebay for not very much. It runs WinXP (the tablet version) and works well, though the unit itself is quite heavy (for a tablet pc; it's lighter than a lot of books). It's a bit clumsy and awkward, and it's not e-ink, but it works fairly well.

The other option I've used is to rotate my 19" monitor to portrait and read that way. Since the monitor is on an arm attached to the wall, I can position it for a fairly long research session without too much discomfort. That, in addition to a Wacom tablet and either Skim or Acrobat Pro, is a good combo.

Drawbacks to both (which a large e-reader would solve), but still workable, imo.

Edited to add: I'm fond of the PDF image format that GB uses because some of the old books I need have the long 's' which wreaks havoc with OCR engines (at least the ones I have).