Lightweight Rectangle Sleeping Bag?

I think it will be hard to find a bag that fits those criteria. Feathered Friends makes rectangular and semi-rectangular bags. However, they are more expensive. My wife and I use the 20 degree Penguin with a zipped in "Toucan" ground sheet. This works like a quilt, but with the advantage of preventing side drafts and being connected to the pads.

Western Mountaineering also makes a semi-rectangular – the SYCAMORE MF – that meets all of your requirements except price ($365). My wife and I have a pair of them (left and right zips) so we can join them. So far, we just carry one, unzip it, and it makes a great quilt for the two of us.

http://www.westernmountaineering.com/index.cfm?section=Products&page=Sleeping%20Bags&cat=Microfiber%20Series&viewpost=2&ContentId=21

25° F rated – and I've been comfy in it closed up at 15°
32 ounces
Microfiber shell for windproofing and water resistance

WM also makes a hoodless version of this same bag, called the ALDER MF, which weighs one ounce less.

FF and WM both make excellent quality bags, but you do have to pay for it. My advice on sleeping bags is the same as on a matress and box spring – buy the very best you can afford. Without a good night's sleep, your day starts off in negative territory when you get up. This is no place to scrimp.

Jack, take a look at the Western Mountaineering Mitylite. It's a semi-rectangular bag that weighs 1lb 10oz good to 40F, but I've had it down to 30. I recall paying less than $200 a few years ago, so it's probably up to $200 by now. A fine bag; however, it is a sewn-through construction, so it's definitely a warm weather bag.

Hey-
I have a Mitylite, nice bag, but sewn through construction–if this is to be your wife's "cold weather" bag, this isn't it. Price is now 285. Western's Tamarack semi-rectangular is $200 and 30*F, great bag, baffled, with lots of loft, 19 ounces–but only 5 feet long, a good half bag or short people bag. The Alder would be a good consideration, but current pricing is $340.

Howdy,

Jack’r’better large family of quilts could be just what you are looking for. My partner and I use one of these as a bag when going solo, and as a quilt when together. They’re well made – we’ve been totally happy with ours.

Cheers
Alliecat

Campmor makes a rectangular down bag rated to 20°F. I'm sure the rating is a bit optimistic, putting it near your 30° requirement. It weighs a bit over 2 lbs and costs about $130, IIRC. I have one that hubby and I use for car camping. I bought it for him to take backpacking, since he's seriously claustrophobic in a sleeping bag, but after our first 2 disastrous trips, he's afraid to go out in the woods with me again… :) Because of the heavier shell fabric and lower quality down, it doesn't pack as small as it could. Still, it might be close to what you're looking for.

If you want to save some cash try the ultralight slumberjack bags. They weigh a hair over 2lbs. I have a Diablo which weighs 3 but also have one of these 2lb 30 degree bags I use as a lend out, I use the heavier bag because its a full 36" wide and even though its only rated to 40 degrees the silver interior seems to reflect body heat, I've used it in cold temps and can use it as an overbag aswell since its so wide.

On request Feathered Friends will make up a Great Auk, a discontinued model that's fully rectangular with a pad sleeve but no down on the bottom, rated to about 30 F. My size Long weighs about two pounds. Priced comparably to listed FF bags, though, surely more than $200.

I have one of these, in a regular Gore-Tex shelled version. It has been seamsealed and is in mint condition and has been warm to below freezing for me.It is a bit too tight for me as I am very broad shouldered and I would sell it for $175.00 USD mailed to you, I have a new Thermarest regular for it that would bring the price to $225.00 USD, if you want it.Let me know at wodaxe@msn.com, this is a superb bag in quality.