Some people use Anoles or House Geckos as feeders. You can purchase "Feeder Lizards" at various pet stores.
I have read nothing that shows it is beneficial for Chameleons and as BocaJan said above there are parasite issues. A chameleon is more likely to be susceptible to a parasite or disease another lizard is carrying vs an insect.
I generally at least like the taxonomic class to be different in my feeders...