From IGN:
Quote
Nintendo has not yet released official imagery of what the controller shell might look like. However, we've created a mock-up (above) based on what we know of its functionality. The real controller shell is likely to connect to the free-hand-style pointer in a very similar fashion. Please note that we realize our model is not entirely to scale, but this is the best we could do on short notice.
Link.
-edit-
I just realised that you noted it was a mock up. I think it would be a good idea on Nintendo's part to use a shell designed like that. It would defitnitly make the whole thing a lot better.