I use this thing.
http://www.youtube.com/watch?v=MFzMVW-8TOcI got it modified to take me down to 0 degrees F. The only thing I need is something on top (medium-weight blanket that encloses my body while being folded over at least once) and a foot pad or a jacket that I wrap around my feet. This got me down to 23 degrees and I was too hot.
It's one of the smaller UQs on the market as it's a 2/3 quilt, therefore it is lighter and more compact. It compresses quite well in my 30L pack too, but I'm a smasher.