No. People are building them with deregulated window AC units. (Pull the original thermostat out, use an external temperature controller.)

It's easier to better insulate a walk in than most modern, lightweight chest freezers. A small walk in would be more space efficient than many chest freezers, and could accommodate a hanging carcass or three easily.

So, more and better insulation combined with less surface area to conduct heat means that you can store more with better electrical efficiency, plus you can use the heat generated by the AC unit for other purposes like pre-heating water which you can use for washing purposes or even circulated through the floors with radiant heat during the winter.