Think Secret claims an Intel-based Mac mini will make an appearance at MacWorld San Francisco in January. Expected to be included in the update, other than the move to Intel processor:
Front Row 2.0
"TiVo-Killer" DVR application
Built-In iPod Dock
Possible move to 3.5" hard drive
Whether the DVR capability comes standard on the mini or as an add-on module is unknown. According to Think Secret, the built-in iPod dock was expected on the first mini, but later scrapped. The inclusion of a larger 3.5" hard drive would indicate the form factor for the mini would increase in size to accomodate it.