I just found this thread. All I can say is, tough crowd!
Unsound, I recently heard Cyndi Lauper do a remake of Etta James' "At Last", don't recall the album, recent I believe but I was shocked. I would have never guessed it was her in 100 years. Flat Brazilian Singers? Different strokes I suppose but having been exposed and listened to a lot of Brazilian music over the past 25 years there are some good and bad everywhere but I will say some of my very favorite female singers happen to be Brazilian. Of course I might be swayed by the fact that my wife is a singer and Brazilian and I have been there many times and heard many artists perform live. Brazilian and American jazz are different. You might want to hear Gal Costa live, I do suspect she might be on your hit list, she does a lot of Bossa Nova. Stylistically there is a lot to choose from.