Hey I'm Daniela, the cofounder of goTenna. Yes, real prototypes have been made. In fact, the final product is done! That's why we didn't go the crowdfunding route because we're ready to move into manufacturing (and in fact already have).
Use our range calculator here (http://bit.ly/1qKVDEQ) to understand what your range will be in different environments and/or elevations. We've gotten up to 3.5 miles in NYC but more realistically, it's up to a mile in urban areas. Up to 50 in a skiing situation outdoors :D
Our first device operates on frequencies that only enable 9600 baud transmissions. So we want everything as tight/small as possible in terms of packet-size so we can have a scalable networking layer
Use our range calculator here (http://bit.ly/1qKVDEQ) to understand what your range will be in different environments and/or elevations. We've gotten up to 3.5 miles in NYC but more realistically, it's up to a mile in urban areas. Up to 50 in a skiing situation outdoors :D