>>2554467i made something like this and didn't like it. you don't really want to expose your sleeping bag to elements a lot of times, you certainly don't want to sweat wearing it, you can't fit a shell over it, and it always fits like a poncho no matter how you design it, which is not thermally efficient. i concluded its good in theory bad in practice.
>>2554417down's the least clammy of anything.
no one sleeping bag covers all weather, unless you live somewhere tropical you usually need 2 to 3 bags to cover the range you'll /out/ if you backpack all seasons.
if you want a 'better' warm weather bag, get a quilt with a zippered or cinched footbox that opens up like a blanket for your 40 and maybe even 10/20 degree bags.
also look for a quilt that comes with 7d or 10d face fabrics. they are noticably less clammy than 15d/25d/etc you find on standard or economy sleeping bags. generally you will need a custom or higher end bag.
