After exhaustive research I settled on the ThermaTEC Series of Peltier modules from Laird Technologies.  Built for cycling applications they can handle the temperatures we desire and are designed to operate in reverse polarity mode on a frequent basis.  With a delta T rating of 64C we can achieveeven the highest temperatures that might be wanted for cooking as well as the below freezing temperatures for flash cooling.  What's even better is the cost:  at $47/unit from Digikey they don't break the bank!