I know there was an episode of Simply Quilts where she made a quilted duvet cover. You might see if there's some site that still has her old shows archived. I used to watch them on DIY or HGTV. The one she did was very pretty, but I don't remember the details as far as construction. Seems like she did a normal quilt, then did the "pillow case" finish with a separate sheet of fabric. But I'm not sure.