I use a quilt for most of my year-around hiking in Arizona. I like it for the same reasons that you are discussing; cold nights, warm days and lots of water weight in my pack. I also use a quilt in the Sierra in the summer. One of my quilts is a home-made, baffled, down version with 2" of loft and a head hole so I can wear it as an insulated serape. The other is the same but with about 1" of loft. When the weather gets too much below freezing, I generally either wear a lot of clothes under the 2" loft quilt or just bring my sleeping bag.

If you make your own quilt, I would recommend that you include a draft-stopper strip down both sides and perhaps across the top. In my experience with a quilt, it is the drafts that will make you cold. So a way of keeping the sides tucked or otherwise draft-free makes a huge difference in how warm you sleep.