Provided Bethesda has kept the .nif format, the way body-types will work is not by modification of the mesh, but by modification of the bones. See this mod for Oblivion:
http://www.tesnexus.com/downloads/file.php?id=29853
You can change the body shape of your character at will with that mod. How it works? Basically, meshes stretch to fit the shape they need to be, as designated by the animation 'bones'. In Skyrim, Bethesda will probably put limits on the sliders, so you can't make your character so fat you distort the meshes/textures too much.
http://www.tesnexus.com/downloads/file.php?id=29853
You can change the body shape of your character at will with that mod. How it works? Basically, meshes stretch to fit the shape they need to be, as designated by the animation 'bones'. In Skyrim, Bethesda will probably put limits on the sliders, so you can't make your character so fat you distort the meshes/textures too much.
But, but, I want jiggle bones. Haha, not necessary.