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Amazon has the 1TB for 199$ (link). It's thicker than normal HDs so don't know does it fit in Mini
 
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It might fit ...

When I upgraded from 80GB to 320GB (5400 rpm) it was the same thickness as the one it replaced. However, I needed to shim up the 320GB hdd when installing it for it to plug in. There seems to be about 3/16" left on the top ...

This was on a 1.83Ghz Core Duo
 
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