Actually I'm a trained sax player. Alas that gets a bit old after a while.. so I went with the wind midi controller. The trick is, if you play a trumpet sound like a sax, it won't sound right, so you've still got to make it sound like a trumpet...
They do make a breath controller for keyboardists... The reviews are still mixed. With practice a person can be pretty convincing with a keyboard and a breath controller.