looking at the hugman models I can see how easy it is to throw in another pair of arms but that throws out the fact that you have pectoral muscles in which to help raise the arms/shoulders and give them strength. Also the stomach and back muscles would be greatly adjusted to form the posture for the lower area and the transition to the upper area. I'd really envision a far heavier set to the lower body to compensate for an elongated spine and the huge increase in muscle (and therefore weight) mass - this area could be a real good study for anyone into anatomy 
back on track...
you're getting a good blocked in area for the body perfecto, make sure you reduce the knobbly knees tho 
looking forward to seeing the progress
Si