Clearly "talent" in programming has a tie-in to things like IQ and memory. While I appreciate the musical instrument analogy, it breaks down on these two elements specifically. I know guys who are "not smart" yet they are amazing jazz musicians - true leaders of the world in that regard. These are guys with probably a sub-85 IQ. Could be they programmers? No, not a chance. They don't have the mental capacity.
So "talented programmers" and "talented musicians" have a different type of talent. Both are simply luck of the draw at birth - if you were born smart and with a high IQ, you can accomplish both (music and programming by practice). If you were born with a sub-85 IQ, I don't think you have the option to become a "programmer" unless there is some other element at work (amazing memory, ability to focus, or something else).
Good question - I guess I see 'talent' most commonly as the ability to quickly turn time applied into results - more talented programmers are productive more quickly in new environments, more talented musicians achieve more with an hour's practice than less talented musicians.
I think my own definition of 'talent' would seem to accord with your 'practice' concept.