Again, I think you are both mistaken.

There are plenty of metal cases out there for devices that don't have external antennas.

Innopocket actually makes them for the Blackberry. So perhaps you should let them know that their cases cause the Blackberry not to work. I'm pretty sure they would have tested this before they started selling them though but maybe not. Maybe these cases are designed so that RF is allowed to penetrate through an opening of some sort?

Here's the one for the 71xx series.



And for the 66xx/77xx series.



They also make them for other devices which don't have external antennas.



www.innopocket.com

The bottom line is the person's request is not far fetched and someone will probably release a metal hard case eventually.