Anybody use a system involving a quilt or down blanket instead of a sleeping bag. I'm more comfortable sleeping on my stomach with my arms tucked under my head and it's really hard to get in this position in a mummy bag. I see Therm-a-Rest makes one (Alpine 35F Down Blanket they call it). Anybody used one or heard anything about them. I'm looking for some way to get a more comfortable sleep and would be willing to carry a little more weight to do it versus my current WM Highlite.