Just like the title says.
From 20 to about -40 F, are there any viable alternatives to using a sleeping bag?

I was reading up on Surplus color weather gear and someone was saying that the Lv7 ECWCS trousers and jacket could be worn instead of using a sleeping bag because they are rated to -40. Theoretically this would allow you to get up and see what that dump was quicker, and they pack smaller than most comparably warm sleeping bags.

-this is assuming you are sleeping in a 4 season tent, with a reflective space blanket beneath you to bounce your heat back on you.-

Picture is the suit in question. It is over sized, so even if it gets really bad or if it doesn't work as well as it says, I could layer up.