A rather excellent rotary mobile made by scientist/engineer Justine Haupt as a “statement against a world of touchscreens, hyperconnectivity, and complacency with big brother watchdogs.” Sez she:
it’s not just a show-and-tell piece… My intent is to use it as my primary phone. It fits in a pocket.; It’s reasonably compact; calling the people I most often call is faster than with my old phone, and the battery lasts almost 24 hours.
She’s open sourced the technical details on her website so you can build your own if you’re that way inclined.