Apple Insider writes the extension files that ship with the latest MacBook and MacBook Pro systems have references to a "Macmini3,1" and "iMac9,1." The current model numbers for the iMac and Mac mini are 2,1 and 8,1, meaning these are references to unannounced models.
Furthermore, the references also list "CFG_MCP79", meaning Apple's upcoming Mac mini and iMac will feature the same MCP79 chipsets as the latest MacBook notebooks.
The entries for the unannounced iMac and Mac minis list their chipset as the "CFG_MCP79," which is the same exact NVIDIA MCP79 platform employed by unibody MacBooks, MacBook Pros, and MacBook Airs, which are similarly identified in the same file as the MacBook5,1, MacBookPro5,1, and MacBookAir2,1.
Also of interest is that the entries for the new iMac and Mac mini are dated 2008, which may provide evidence to support claims that these systems were originally targeted for a release in the November time frame but were pushed into the first quarter of the year due to unexpected delays.