This website has embroidery machine covers for a few machines.
http://www.ericas.com/embdesigns/dress-it-up.htm
I upgraded from a Brother 8500D to an Innovis 4000D. I took the cover I made for my Brother 8500D, opened up the top so it would slip over the bigger Innovis and used a plastic sewing machine cover to cover the thread rack. It says "front" because I could never quite figure out which side was which when I put it on!