Well, as far as making regular "Graal bodies" go, with no shading at all it might be a bit more difficult. But probably what I'd do is I'd go about making a regular body, and shade it accordingly as I go. If you use Photoshop, it should be as easy as copying the layers of the shading over to the mask side. If you don't(like me) it would just mean copying all the shading over, coloring it to black and white and erasing it from the normal body. Not really the hardest thing to do as far as creating a mask, it's just the effort of having to shade your body as well that would be time consuming.

This is basically what I had in mind a lil after what I said about the gani edit stuff.