St. Louis, MO's Coultrain is a folklore. One man simply not of these times. Although, to style him as a ''revivalist,'' or a ''futurist,'' for that matter, would be as ill-suited for this particular outfit as are the fleeting trends of today. As much a storyteller as he is a story, himself, still unfolding; the man takes many forms. First, there is Aaron Michael Frison, an estranged poet of whom not much is known - who, although his work is deeply personal, his own life story has been told best by the found letters of his lovers past, or through its most famous interpretations by Coultrain - a St. Louis blues & soul man, born to the marriage of a preacher & muse, who would come to carve his young niche in the world by singing his unconventional tales over not so &''standard'' jazz pieces.