I am in as well for building the next version
See if you can find any 12V 40mm square Peltiers on ebay. I retract my word when I said we can/should use >12V Peltier so it does not run at 100%. PWM will do this for us and we should not limit ourselves from the start to reduced performance.
Also if looking on ebay, the descriptions of Peltiers have lots of incorrect/misleading information. It looks like lots of descriptions were copied/pasted and some corrected and some not.