Just a heads up that Chris Lord from the Vaani team reimplemented the Amazon Echo using open source libraries and node.js.
His project is compatible with the skills API and as such can be used as a drop-in replacement of the Echo. He wrote in details about his project at http://chrislord.net/index.php/2016/06/01/open-source-speech-recognition/ and the code is available from https://gitlab.com/Cwiiis/ferris
His project works offline (except of course if a skill needs an internet connection).
If Echo skills are so easily to reimplement, why not add them to Project Link and benefit from a free and rich ecosystem from day 1?