Because this is an input device, I would love literally any form factor other than glasses. Smartglasses had a stigma back in 2012 when I was making them out of duct tape and beagleboards. Behind the head, in the same format as bone conduction headphones (even if there are sensor wings protruding forwards) would be so much better. In fact, combining this with bone conduction would make for a full silent and internal communication device.