I'd say your two options are a heat controlled room build, or a water jacket.
Easiest: Room build. Window AC unit and small heater. Two stage temp controller.
Smallest footprint: Water jacket. Wrap 3/8" soft copper coils around the outside, then insulate well. Constantly circulate heated or cooled water through the coils with a small pump, and temp control the circulating water via an aquarium heater or water cooler, you should be able to hit your desired temp in the chamber.
PS: best avatar ever....