I've made two duvet "quilts". The first was a wonky log cabin on muslin backing. Good thing it's on a twin down comforter because it's VERY heavy. The back is six large log cabins.
The second I made just recently. It's made of 12 inch square Kaffe fabrics with a 1/2" black sashings and wide Kaffe backing. No quilting at all. It's on a king size down comforter. It ended up in our RV cause hubby liked it so much. We spend half our time in the RV so that's OK. Now to make something else for our bed at home.