Not quite duct tape... but hack none-the-less.
The yellow lanyard is something I got from work. My company does registration for trade shows and part of that is making a name badge with bar codes that contain all registrant information. We have all sorts of goofy lanyards around. It has little clips on each end.
I use the normal mounting neck/pivot to clip the one end of the lanyard to after wrapping some of the lanyard around it to get the right length, then I doubled/knotted the lanyard and clipped one end to keep it there and I clip/unclip the other end when I hang it on my neck. The wire leg with fuel line rests against my body, but helps it stick to me vs sway back and forth, also helps remove wire on cloth noise the camera mic picks up. I can twist it since I just have a 3mm bolt/washer holding it onto the hero frame to keep it pointed where I want it.
The neck of the holder pivots, so I can fold it down and it will point the camera more at the ground, for when shooting my truck down in a skate park bowl or something. Or I can pivot it up to shoot in level with me.
Looks stupid, but it works at giving me both hands free while not being a tri-pod, so I can move with the action by twisting my body instead of my head when I drive. With the lanyard cinched up pretty high, I rarely pick up my remote antenna in it. Of course ,it sways and moves when I lean over or walk, but I edit all that footage out because it looks like crap anyway.
The camera ends up upside down, but most cameras let you adjust for that. The gopro does it automatically and rotates the screen as well. My old camera just rotated what was recorded.
I suppose a full on chest harness would work, but then it feels like your being strangled by a really weak guy all day. I looked for days online trying to find something like this, but nothing really exists, except for a phone pouch.