AppleInsider is reporting that the speculated refresh for the iMac and Mac minis lines might include NVIDIA graphics chips. This information was discovered while an InsanelyMac forum poster found some extension files included with the new MacBooks/MacBook Pros. The exentions were named, "iMac9,1" and "Macmini3,1."
Currently shipping iMacs and Mac minis have the model numbers of "iMac 8,1" and "Macmini2,1," respectively. The kernel extension .plist file is part of the SMC (System Management Controller) and ACPI (Advanced Configuration and Power Interface), and made reference to "CFG_MCP79."
The MCP79 is a graphcis chipset offered by NVIDIA that is found on the current line MacBook, MacBook Pro, and MacBook Air. For more information, you can read the forum posting at InsanelyMac.