Well walkinTas, if you acknowledge my reply then I could continue
I have two of the other options on those linked pages (Outdoor research) which have had a Lot of use and have tried a third (Bibler) which was used a few times...
(there is a short video of the Marmot there though they seem to be outa stock...)
Currently for really light weight I have a mountain laurel bivy. It can be carried with a small tarp and groundsheet at still less weight than the heavier bivys...
As franco suggests, what are you looking to achieve? (I wouldnt Like to spend a wet night in any bivy (on its own)... If you would like to... hold on... I wasnt going to continue was I....
