lolol Carlos Santana doesnt sing. I believe he used to do vocals back before he was signed, in the early 60's, but nothing has ever been released with any extensive vocals by him.
I take you have never heard of The Product G&B (Ghetto&Blues). They were 2 male soul singers that have done a lot of work with Wyclef and Refugee Camp. They sang the vocals on "Maria Maria" as well as Pras' "Blue Angels", and there's a great track they did with 50 Cent in the late 90's, named "Tired Of Being Broke"...
I know they recorded an album with Columbia, but I'm not 100% sure whether it ever got released. Some of the tracks from it are leaked though, and can be found on filesharing progs. I believe they may have had a falling out with Wyclef. My manager manages Wyclef and Pras, so I'll find out of he knows what happened to them, most likely he will.