I have created 2 different "Torso" cakes. One a Red Corset http://cakecentral.com/modules.php?name=gallery&file=displayimage&pid=1343301
and the other a Cheerleader (available in my pics). I used to small ceramic bowls to create the breasts. I leveled them to make sure they were close to the same size. I use a 18x12 pan and trimmed to look like a torso. (I have created a pattern out of cardboard that I used for these cakes, that way they are equal)
I mounted the breasts near the neck line, then cover in BC to fill in any gaps. Smooth with a roller. I covered the 2 cakes in several pieces, instead of trying to use 1 sheet. (Easier to work with) For the cheerleader, I did push the fondant covered breasts together, to give it a "push-up bra" look, otherwise try to make it look natural. Adding nipples to the breasts also gives it a more natural appearance, but not required.
The rest of the body is up to you. Cover in the corset of your dreams, but most of all, have fun.