[Don K]

I built one this year. 8x9x8high. Have a window shaker and a coolbot. Had 2 antelope in it for a week and later 2 elk for 8 days. Kept it at 34-35 the whole time. Works like a charm.
I insulated the walls, floor and ceiling, vapour barriered it then put styrofoam insulation and another layer of plywood. Siliconed all seams and then used rubber paint on entire inside. Put a vinyl floor in for easy cleanup and track on ceiling with 10 hooks.
It cools within minutes from room temperature.