Magnet Schools of America provide a wealth of background, history, examples, research and rationale for thematic or magnet schools. For instance, there are 14 elementary and secondary schools under the International Studies group and 79 magnet schools under Fine and Performing Arts. Each of these have links for further info. Also, an article on a MI magnet school.
They list as rationale for magnet schools:
-that all students do not learn in the same ways;
-that if we take advantage of a student