Jacket based sleeping system

In 1975 while on a 30 day Greyhound bus pass trip from So Cal to the Canadian Rockies, at the one and only REI in Seattle WA I bought an expedition down jacket for $75 (5″ loft, the common way in those days to measure how warm stuff would be).  Also a pair of expedition down pants for $25 (3″ loft).  The pants had zips on both sides of the legs and could be zipped together to make a 2/3 sleeping bag, the opening at the bottom had a drawstring to close it down. I used this as a sleep system and it worked pretty good.

I also had an expedition sleeping bag with 9″ of loft, a lighter weight down jacket, and a down vest.  I stayed up in the Canadian rockies until December, lurking around Banff and Jasper. Many nights it was so cold I was in that sleeping bag with all my down on!  I finally left after a -40f snap and went to work as an unpaid slave at my dad’s nightclub in New Orleans – one month of that and joining the Army looked attractive, so I enlisted.

$100 for a down parka and pants- those were the days :)

What about the Patagonia hybrid bag? Seems a legit option for this kind of system.

it certainly looks like it would work, paired with the right jacket

interesting top portion- would help keep heat in/drafts out, but guessing not overly “weather protective”, probably still need a bivy