I think it will be an additional button that will be available in the Move command at the "Pick base point" prompt, the button will say something like "From center" or "From bounding center" or something like that, and when you push it the center of the bounding box around the objects being moved will be used as the base point and then you'll go to the next stage and pick the target point and you would be able to type 0 and push enter there for specifying 0,0,0 as the target.

There is also a command that you can set on a shortcut key that will generate a point object at the bounding box center location, it might be useful to you:
http://moi3d.com/2.0/docs/moi_command_reference10.htm#boundingboxcenter

- Michael