Maybe my question was a little unspecific.
The most natural way for me would probably be to upgrade to the Kindle Paperwhite. Obviously it has no buttons and few memory without sd slot, but it is said to support WPA-Enterprise, has linux compatibility, collections and dictionaries.
What about its panel view mode? Would it be usable to read the columns of a document like
www.aip.org/pubservs/style/4thed/sec2.pdf ? Is it posible to fit the screen width to only the middle column in
http://arxiv.org/pdf/1304.0405 ? Will I then have to zoom again on every page or are the settings stored?
As far as I know there is no version of the kindlepdfviewer for this device (yet). Are there other alternatives (besides cropping the document on my pc)?
Are there things I might not like about the Paperwhite and which advantages (at the cost of which drawbacks) do other readers have in comparison?