Cathy,
I use a whipped topping mix made by Kineret (Pareve) which is a good
substitute. It is distributed by Kineret Foods Corp., Jericho, NY 11753 and
is a product of Canada. I bought it in the kosher area of a food store in a
metropolitan area. It comes in a box and the powdered mix is combined with
water and beaten.
Several years ago, I was able to purchase a product made by Rich. I was in
the frozen food section and looked like a very large can of frozen orange
juice. It was a frozen topping and was delicious. I have not seen this
anywhere recently, but Rich Foods still have other products in the frozen
food section of the stores, so perhaps a search of the internet would turn
up something for you.
Jane