Heh, I know what you mean, its hard for me to sneak out without my wife! She insists on tagging along.
For a long time we used the old “Thermanest” sleep system which was a single long, rectangular, synthetic bag as a top quilt zipped to a sheet that held two full sized pads in place and had a zipper that matched the bag.
This system worked very well indeed! Never any trouble about the quilt moving off ya at night, surprisingly roomy inside ( we snuggle anyway ) and very warm because of shared body heat.
It isn’t made anymore, but Thermarest still has something similar, the “Down Coupler”. Looks about the same but has snaps instead of a zipper to connect it to the quilt.
http://cascadedesigns.com/therm-a-rest/pillows-and-bedding/down-coupler/product
I bet it is very comfy indeed!
Recently, my wife sewed together a Ray Way quilt kit –
http://www.rayjardine.com/ray-way/Quilt-Kit/index.htm
And that will probably be our new quilt. Sewing synthetic quilts is actually kinda fun! I’ve even started making some!
For starters, you may wish to do as I did, and make a simple quilt out of ordinary off-the-shelf stuff, instead of expensive mail order material.
I used 1.9 once nylon ( the lightest the local fabric store had ) for the top, fleece for the inside lining ( heavy but oh so warm and we had it laying around ) and ordinary 6 ounce polyester quilt batting for the insulation. Yeah it is a tad heavy and bulky, but so what? It is a useful quilt and it was a fun learning project.
The Ray Way kit showed how to tie the quilt using a mandrel and I think that is a key point, so you don’t create cold spots by tightening the ties tight as you would on an ordinary “inside” quilt.
Another possibility is to simply buy a nice single ordinary rectangular synthetic sleeping bag and use that for the top. It should be plenty big for two. Make a bottom sheet out of whatever strikes your fancy with a zipper that matches the bag. Turn the sheet over and sew in a short pockets on the bottom and top of the back to hold the foot and top of the pads in place, and an elastic band across the middle to hold the middle of the pads in place.
The sheet-on-the-bottom-that-matches-the-sleepingbag-on-top method is a little heavier but probably a little more comfy and certainly stays in place better than the loose-quilt-over-just-a-pad method.
When hiking, my wife carried the one sleeping bag, the two pads and the joining sheet. This made for a bulky but light load for her, which was good because it prevented her from filling her pack with tons of heavy “Stuff”.
I’d carry the tent, stove and all our food for the trip. This way we cheated – Each of us had to carry only two of the usual “Big Three” heavy items ( shelter, sleep system and backpack itself ).