I never said that the iMacs would be behind. You can already get i5 and i7 iMacs. I would not be surprised if all iMacs move in this direction. However apple like to keep a distinct difference between the iMac and the mini. Which would mean that I would be pleasantly surprised if the mini went i3 and completely shocked if they went i5. I don't think that i7 is even a possibility. I also doubt that macbooks will be updated next week, MBPs yes, but not macbooks.
I honestly believe that it will be between 3 to 6 months after the MBP is updated to i3/i5 that the mini will be, and as I said before I would if not expect, would not be in the least surprised that there was, one more update that is C2D.