A local furniture store received six foam couch cushions with no couches to go with them. They gave me the cushions and I remade them into dog beds that were sold to raise funds for the local animal shelter.
I removed the original covers that had short zippers and made new covers using 60" duvet zippers so that the covers could easily be removed for washing. I used the tutorial here http://houseonhillroad.typepad.com/photos/put_a_zipper_in_your_pill/index.html to make a lapped zipper that hides the zipper and hopefully makes it less interesting for dogs to chew.
I was in a hurry to take the beds into the shelter, so unfortunately I didn't get a good photo. Click on the image for a larger pic.