This is the BEST pillow mattress tutorial I found! This lady actually took MEASUREMENTS and she describes how to make a 4 or 5 pillow bed. Pin this one! OR buy pillow cases, sew together, stuff w/pillows, velcro ends
DIY Eye Pillow -- They help to ease any tension around the eyes , allowing the muscles in the face to release more. And with a wonderful lavender scent, the aroma itself is relaxing too.
DIY Giant Floor Pillows (a fun sewing craft) could also use for dog bed.