Amazon has released step-by-step instructions for building an Alexa terminal out of a Raspberry Pi 2 or 3:
http://www.zdnet.com/article/raspber...tag=TRE17cfd61
https://github.com/amzn/alexa-avs-raspberry-pi
This allows Alexa access outside the markets where the Echo, Dot, and Tap are sold.
The design is Tap-like in that it requires pushing a button to activate the microphone but the build cost is significantly lower than even the Dot. (~US$50, maybe less.) And not much of a handicap for audiobook playback or Kindle ebook TTS.
Given the flexibility of the Raspberries and the ingenuity of the hackers interesting things will be forthcoming.