Hinge to a child, Parent has rigidbody

I would like to hinge to a child object, however to be able to hinge, the child must have a rigidbody. The parent also has a rigidbody, according to the manual, you should never have a parent and a child both with a rigidbody. If i remove the child from the parent, then it will no longer follow the parents position. Anyone have a workaround?

If the parent moves, the child moves with it. But a hingejoint between child and parent would conflict with that. One solution is to move the rigid body of the parent down to the same level as the child. The parent would not longer have rigid body.

before:
     parent (rigid body #1)
         child (rigid body#2)

after:
     parent
          newobject (rigid body #1)
          child (rigid body#2)