There are definitely many high-fliers in all genres. I would propose Django Reinhardt as one, certainly -- quite incredible playing, and all despite the fact that he could barely use two of his left hand fingers.
But 'greatest'? No such thing. All the 'greatest' this and 'top ten' that and 'best' the other, it's complete cobblers IMO. Music is a way of life, not a bloody competition.