Indeed, I can't think of any which did it with a specific character (or characters). I can imagine a series which used a leitmotif for each of the regular characters throughout, and I wonder how many people would notice on a conscious level but still be influenced by it. If I had the power to create such a series, and knew a sufficiently good and subtle composer (I always knew that I really wanted to direct a film or TV series) it would be an interesting experiment.