I have never seen such a pattern, but they should be fairly easy to make. This web page has several free slipper patterns. Perhaps one of those can be modified to do what you want it to.
http://www.sewingfreebies.com/slipper.html
Years ago, when I was bowling, you could buy a half cover that slipped on over the sole but not the heel and covered half of the top of your foot. It had an elastic piece that went behind the heel to hold it in place. It sort of looked like those new pot holders that are just 2 pieces and fit right over the end of your fingers.
Another idea would be to get some of the doctor's covers for their shoes and modify it to fit a bowling shoe. The doctor's shoes aren't enough protection, but would show you how to start.