Even though I may not be actually getting my "my Jareth" doll until some time next year, I've been thinking about bodies for such a custom head.
At first, I was thinking about a Dollshe body, as that was the body that my first Jareth BJD had. Dollshe no longer makes the exact type of body that Jareth BJD 1.0 had, but it was something like this. Unfortunately, Dollshe's bodies are just really aesthetically unappealing and clunky, even though they may have fixed that stomach popping out problem endemic to the first release of bodies. Jareth 1.0 always felt like he was top heavy.
Then I discovered Doll Chateau's Adult male body, which could best be described as elongated. It is the scrawniest male BJD body I've ever seen. It's also a beautiful piece of sculpture, much more simple and much less fussy than Dollshe's. I actually really love it, especially because that's the shape that I'm looking for for my Jareth BJD.
The only thing with the DC body is that it's really easy to mess up the proportions. It needs a tall, narrow head to go with the tall, narrow body so that it doesn't look bobble-headed. If I were to go with the DC body, I would have to give the custom sculptors specifc instructions to make the head a certain size [height, width, depth] so that it fit the body's aesthetic.
Holy crap, that is a skinny body!
EDIT: Dollshe heads actually work pretty well on the Doll Chateau Adult male body.