I too had great luck with a RayWay two-person quilt kit. Fairly easy to make, clear instructions, etc. A bit tricky to sew through the thickest layers of insulation, but I managed. The split-zip is great...we each carry half the quilt.
So far we've only used it down to 40 degrees, where it worked quite well. I think we got the "alpine upgrade" version. Anyway, my wife an I are very happy with it.
Note...draft stoppers are essential, on the RayWay quilt and on any other quilt, unless it somehow tucks under you.