Though while I see hearing aids that fit in the ear and last all day but I don't see bluetooth equipment anywhere near that, I presume the power requirements of radio are high enough to make it harder to put things in anything but clunky glasses without a lot of work. Though it's possible that thicker over-ear components could hold enough battery if on both sides. Mic in the bridge could be useful. Actually, mic in the other ear from the speaker might be best because you want the mic to pick up as little audio from the speaker as possible (saving you echo cancellation.)

A good headset built into glasses might actually make a decent headset for people who don't wear glasses, for use at the desk. The glasses would sit in a charger, and have flat "lenses" or no lenses at all. But glasses are easy to put on the head, and if you happen to get up and walk around with them, don't look as strange as headband headphones, which are the other thing that's easy to put on. For short term use, battery size can be smaller, and standby mode is not needed.

Another possible design is a hat. This can also be stylish. However, the further the speaker is from the ear, the louder it has to be to others and to the microphone. Perhaps a hat where the speaker flips down unobtrusively from the rim. Microphone on the other side of the hat. Of course a hat has lots of room for batteries. There was a time when everybody wore hats outdoors and every building had a place to hang them. One could imagine people wearing their bluetooth hats (radio heads?) outside, and having a pocket earpiece if they need to make a call indoors.