There are some unofficial photos of the interior [1]. Its severely lacking, with a large screen just tacked on to the dashboard with no interface whatsoever. Musk says model 3 will be a smaller, less advanced version of the flagship S [2].
https://c1cleantechnicacom-wpengine.netdna-ssl.com/files/201...
http://bgr.com/2017/03/24/tesla-model-3-release-video-musk-o...