One HardMac reader claims that his new Mac mini shipped with a Core Duo 1.66GHz instead of the advertised Core Solo 1.5GHz as well as a larger hard drive (100GB) and Superdrive (instead of Combo).
The site believes this represents a silent upgrade across all Mac mini's consistent with recent rumors of upcoming Mac mini upgrades.
Alternatively, it may simply be a mistake, unless there are multiple confirmations of similar upgrades. Of note, Apple has done a similar silent upgrade in the past for the Mac mini.
Meanwhile, there is more confirmation that Apple will be hosting a media event on September 12th.