I agree Jack. Typologies of any amount (call them humours, star signs or archetypes, same thing) as you say, are found throughout the history of human culture. Natures own fundamental tendency to organise and constellate random fragments into some kind of cohesive semblance of wholeness, is echoed by our own tendency to observe and attempt to catagorise that phenomena.

My philosophy teacher used to refer to one of his fave philosophers philosophies by saying "I'm Jumble Man!", meaning he was just a collage of bits and pieces generally hanging together. Yet it's THAT tendency for random stuff to morph and organise itself into patterns which we also somehow recognise and recreate, which is at the core of repeated motifs wherever generated and recognised. Be they as 'characters' in folk song, or indeed in Trinny and Suzanna's body typology. Something tells me however, that T & S's typology will be a little less long lasting than J's archetypes.