The new Kindle DX has a large e-ink display and it can open PDFs natively, where as Kindle 1 and 2 needed conversion. Haven't used one myself, so I can't comment on the quality/readability, but it sounds like exactly what you're looking for.
With regards to the Kindle DX, I think I am a little afraid of the DRM issues which for one reason or another might make it a brick because I am either in the wrong country when I am reading something or else. The DX is also not in the hands of users, as it will begin selling later this year, I am really looking for the point of view of an actual user of a real product that one can already buy.
Igor.