Intel has the 65W Core 2 Quad S Series. They're power optimized, lower voltage bins of the normal 95W Core 2 Quads.
They would drop right into the current LGA 775 socket on the 21.5" and base Core 2 Duo 27" iMac. It's a possible upgrade path for the LGA 775 based iMacs without redesign the logic boards.
The Core 2 Quad 8400S or Core 2 Quad Q9550S would be fine options to the line up as a BTO. It should be BTO today but sadly it isn't.
It would be like Apple using Athlon X2 while everyone else has moved on to Penryn. The only iMacs sporting a 2009 level processors appropriate for the market above $800 is the Core i5/i7 iMac.
Core 2 Quad has lived at $500-600 for almost two years now. It's a shame.
well i suppose apple is targeting the casual user, AKA 90% of people. I guess it's logical seeing how thin the iMac is and how much they're trying to keep prices down.