* full rectangle bags that open flat and mate top over bottom
* 20 degree rated
* synthetic fill
* waterproof shell if possible
The only waterproof shell bags I have found are higher-end down expedition mummies so I think your guess that a mild climate rectangular doesn't come that way is correct.
I listed those ones from Campmor because I had been looking at similar bags myself for us to use in our small camper trailer. Also, since I mentioned the Goretex "slipcover" I had made for the sleeping bags, I checked on Ebay and found some less costly Goretex than that from Seattle Fabrics. If you feel up to making something similar there is a guy selling military camo and also navy blue goretex nylon for under $12 a yard (58" width). At that price you could construct a double bivy bag for under $40.
Overstock Outlet Foods
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