CloudLite

If you can swing a WM bag, it’s so worth it.  FYI - I got 20% off of mine from REI last year! Their sale ends on the 24th!

I did, with overfill. I've only slept in it two nights. Low of 35 f so not really testing it. But it was very toasty. So much so I had to sleep with it unzipped. That's on a Nemo Tensor Extreme which I'm still making my mind up about.

you might take a look at this: I can tell you this company is known as "The Mercedes" of sleeping bags and they have something extremely close to what you are looking for. Their temperature ratings are generally regarded as "conservative." I can go into more detail about that if you want. Their ratings are "comfort rated" (not survival rated) and still conservative. You would be going from a rickety Cessna to a G5 Private Jet plane. If you pair this with the right high R-rated bag and layer right (sleepware) I think you'll be great. Bonus they make a 5'6" bag. I've used their bags over 30 years and can't say enough great things about them. [https://www.westernmountaineering.com/product/cloudlite/](https://www.westernmountaineering.com/product/cloudlite/)

Almost forgot- there is an option to add "overfill." You can 1) special order it through the dealer 2) order the bag direct from WM (they ship uber-fast, fyi). The cost of the overfill adds $59. Not sure you really need it but wanted to let you know it exists. I think you will crush your requirements. I know the quilt recommendations are awesome products and the comments about "squishing the fill" aren't inaccurate but ... i've got a feeling you are a VERY strong hiker and a 2lb 3oz (or 2 lb 6oz) bag will not be an issue for you to carry backpacking. I'll go an extra step where I spend a good deal of time each year (in Colorado) you may have a doppelgänger who has blitzed passed me multiple times. You've got this and the company is top-shelf.

I hope it lives up to how much I hyped it. My favorite test of any bag is the "snooze test." Basically you get in and if you immediately tune out everyone and everything around you and basically feel like saying "uhmmm I good- thank you-- can you (to the sales associate if they hover) give me a few minutes to really get a feel for the bag?" (and then start to drift....) it then squarely passes the "snooze test." Hope it works for you! Post how it goes - yay or nay.

You have (totally unfairly) stumbled into a really under-served market niche. Most rectangular sleeping bags are aimed at car campers, and they won't be warm enough or perform well enough for what you need. And most makers of performance sleeping bags and quilts that emphasize weight make mummy styles only. I'm not plus size but I am a side sleeper, and a more generous cut is crucial. Western Mountaineering is one company that comes to mind that makes high-end, performance sleeping bags and also includes some more generously cut styles (semi-rectangular) among its offerings. [Spec page for all their bags](https://www.westernmountaineering.com/about/sleeping-bags-specification-chart/). Maybe something there could work — like the CloudLite? WM bags are really expensive, but they are a big enough company that they have real life stockists, so you can try it out, and you can occasionally find their stuff on discount — I got my WM bag using an REI member 20% coupon during an annual sale.

Try Enlightened Equipment. The Conundrum and Convert come in a x-wide 70" shoulder girth and extends down a ways toward the hips at that width. Conundrum has a 3/4 length zip and Convert has a full zip opens like a blanket. You can order them in 10, 0 and -10F warmth ratings. You would need to add a hood because neither one has a hood. Another possibility is Western Mountaineering Cloudlite, although it is a 15 degree rated bag. It has a 65" shoulder and 68" hip girth. Conundrum and Convert can be used a quilt unzipped and might work if you can learn to stay warm using a quilt.

This 6’4 270lbs male. I have the CloudLite. I love it.

I own 3 WM bags, so I am biased. For me, they sleep about 5 degrees cooler than recommended. So, their 15 degree bags takes me down to 20 degrees in silkweight undies, no fleece, no down. So, if it were me and I wanted to go to their true spec, I'd get overfill. Just depends on what you want, look at overfill as an option to go a few degrees cooler.