Would require you to double check all of your measurements and to cut carefully!! That is why I prefer to use more economical fabrics, such as this pillowcase from Dimmey's, which cost me $2 for the set. Go Dimmey's.
My pillowcase dress ended up with some side splits because I unpicked the bit that slips over the pillow. I like it. Thanks to Chris for the orange ribbon which was part of my goody pack from the bag swap.
Don't look too close, it's rough in places. Lucky I wasn't using Japanese cotton.