Designer daybeds for dogs are available at any pet-supply stores in many different designs. You can, however, design your own simple daybed for your dog for a lot less money. You can make one that will better fit your room's style, and your dog may even find it more comfortable than any store-bought beds.
Take a fluffy cotton-filled pillow. Do not bother with an actual pillowcase, as you will be making your own cover. You may need multiple pillows depending on the size of your dog.
Assemble your pillows into a square. Measure the total length of the assembled square and then measure the total width of the square. Cut out a sheet of canvas fabric that is equal to the pillows' length and twice the width, plus an inch or two longer on all sides.
Fold the fabric in half so it looks just slightly larger than the surface area of the pillow.
Sew the two side edges of the fabric together -- the two edges that connect to the fold -- using your sewing machine. You will now have the equivalent of a large pillowcase cover in the design you want.
Turn the cover inside out and put the pillow in it. Fold and tuck the open end of the cover underneath the pillows to close it up and complete your cushion.
Place the cushion into a shallow woven basket large enough to contain the cushion to complete the bed.