I don't know of a pediatrician near Medina, but if you are willing to go to Rochester, I highly recommend Dr. Tom Rossi at Strong Memorial.  He is a pediatric GI and is incredible.  He will also explain to a pediatrician how Celiac works.  There are actually pediatric GI docs who believe the same as your pediatrician.  That small amounts of gluten or gluten reintroduced after "healing" is no problem.  That is why we travel from Buffalo to Rochester to see Dr. Rossi.  He also sees patients in Batavia one day a week.  The only problem you may run into is that you need a letter from your pediatrician in order to get an appointment because he is so popular!