I would suggest that you use a mummy bag with a full length wrap around zipper. I use a North Face Cat's Meow in my Clark Jungle Hammock. If it's a warm night, I unzip the bag completely and use it as a quilt, or even sleep on top of it. If it gets really cold, by using a bag instead of a quilt, I can zip the bag up by degrees to find the comfort zone I want. Using a quilt does not offer you the same heat retention, when needed, as a sleeping bag does. I also use a Therm-a-Rest Pro Light 4 mattress under my North Face bag. The combination of hammock, mattress, sleeping bag, and mountain air makes for a terrific night's sleep.

Just consider... if quilts had been the ideal sleeping accessory on the trail, then sleeping bags would have either never been designed or they would have fallen out of favor quickly. I like quilts very much, I have one my Apache Indian grandmother made by hand, but it's on my bed at home, and my sleeping bag is in my backpack along with my hammock.