Play.com posts a product listing for a Core 2 Duo MacBook duo for release on November 13th, 2006.
The accompanying specs simply describe the current 2GHz Core Duo MacBook, however, so no additional details are available.
A release date listing of November 13th is particularly specific and in line with circulating rumors of an updated MacBook before the holiday season.
That being said, Apple resellers have never been given pre-release information for exactly this reason, which means that this information is far more likely to speculative than based on insider information.