In the meantime I wanted to share the 2 sources for wheat free- gluten free dough. This first resource was sent to me from kidsfoodallergiesblog.com . It is Colorations® Wheat & Gluten-Free Dough which does not contain the following common allergens: Latex, Dairy & Casein, Egg, Gluten, Peanut & Tree Nut . It looks to be a modeling clay that you can use to mold shapes and leave to harden. I am glad to know about this now. I had looked into purchasing modeling clay for my children from the craft store. However, there are no ingredients listed on the package so I had no way of knowing if it was safe.
Next there is another product from Aroma Dough. As their web site states "ALL products are Gluten Free made with 100% organic, wheat-free rice flour, sodium, water, moisturizing oils, natural aromas (no perfumes). This formula is perfect for children who have special needs such as Autism, Celiac’s Disease, ADD/ADHD, or other allergy related issues. It DOES NOT contain nuts, nut oils, perfumes, soy, dairy products or wheat."
I have purchased this and my kids love it. It like your traditional Play dough, but it is gluten free. It is also scented - each color is a different scent. It has also last us quite a long time. They also sell large buckets of dough for $19.95 that would be an appropriate size for a preschool class. Based on our experience with this dough, I would recommend it.