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I'm definately no metal-worker but I can't imagine making the 'bar of soap' shape from Aluminium'd be easy.

It wouldn't be a problem to make a mouse shape from Aluminium.

I don't think they will though. The new Mac Pro that was released this week now has the Aluminium keyboard so if there was going to be a new mouse I would have expected it to be included with that update.
 
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