http://www.belasantacatarina.com.br/...riu/1-1-0.html
That is a list of some hotels in Balneário Camboriú.
The standard for guides is Quattro Rodas and this is their guide to the place:
http://viajeaqui.abril.com.br/destin...eario-camboriu
My favorite hotel there is:
http://www.resortrecantodasaguas.com.br/
I absolutely agree that with the criteria you stated this is the place! There are a gazillian options in the Northeast, of course, and in lots of other places but this one is special.