In Rio de Janeiro there are quite a few options, vegan and not. Here's a list:

http://www.vegetarianismo.com.br/sit...=127&Itemid=92

Vegan, Vegan is one of my favorites. the national dish, feijoada, is served in a vegan from and is delightful. I have even taken carnivores there without complaints, although I was the one paying the bill.