Hi guys,
i yesterday i watched this Movie on my Youtube Sub´s. I dont test it by myself in the moment, but i know a lot of people want this. The Movie shows how you get a Raspberry PI 3 (ONLY a Raspberry PI 3) to work (after the Config) completely without a SD-Card in the Pi.
Raspberry Pi 3 USB SSD Boot by ExplainingComputers
https://www.youtube.com/watch?v=ubnwvxF3Klc