I know I don't want to go on a tour of the favelas.
I wouldn't be so hasty to cross off the favelas. I know it sounds like a poorism tour, but people are usually pleasantly surprised at what they find. Very friendly people, arts and crafts, spectacular views, and really interesting architecture. Also, much of the tourism profit goes back into the communities. For example, Marcelo Armstrong's tour helps support a school there. You may very well find the tour delightful and informative as opposed to simply voyeuristic (gawking at the poor). In fact, Americans and Europeans have started moving into the favelas because they like the people and the atmosphere.
http://www.favelatour.com.br/