Thinking about the Piano tuner's urban bivi gear for rapid getaways - a bag and a jacket etc in one. Daft or clever, I'm not sure ) I did see those sofa-dweller snuggy things a while back and think about bivi suitability so what do I know..
Sort of brilliantly weird. Strangely I couldn't find any weights mentioned on website. There is also the wackily named mucusbag (snotbag?) http://www.musucbag.com/en/index.html but that weighs 1.6kg. I much prefer buffalo shirt and montane extreme salopettes for really wet weather/packrafting, instead of down bag but don't tell anyone cos that is a pretty warped and heavy fetish I have.