The Raspberry Pi is all about low-cost computing, which makes this particular hack quite fitting, as it allows you to make a terminal for your lil' Linux machine out of something you may already have at home: a Kindle Paperwhite. Displeased with the glare from his laptop's screen on a sunny day, Max Ogden was inspired to find something better and ended up with this Paperwhite hack. It builds on the original "Kindleberry Pi" method for the Kindle Keyboard, although Ogden had to massage it for the newer model and added some extra hardware to make the setup as wireless as possible. You wouldn't call the end result a monitor, as such -- the Paperwhite logs into an SSH session running on the Pi, so it "pretty much only works for terminals." That's probably for the best, as Ogden guesses the lag between wireless keyboard and e-ink screen is around 200ms, but at least it has portability, battery life and sunlight readability in the 'pros' column. Details of the project can be found at the source below, meaning only time (and probably, a few peripherals) stands between you and the ultimate hipster coffee shop machine.
Amazon Kindle Keyboard
Raspberry Pi A/B