Celeron???
I don't think it would be cost effective to put older chips in the mini when there are newer ones available, unless there is a problem with a more recent chip.
There was speculation before that the DVR would be a creation that would be based on the mini. Therefore, the mini would stay 'just as a computer with frontrow added' and a new line (under a different name and sharing no relation to the mini) with DVR functionality.