I don't think the internal measurements are quite that big, but for keeping low-power devices at a constant temperature you might want to look at the "Reptile Incubator" as seen on EEVBlog video. With this TEC heating/cooling I can control the temperature from <+10C to +60C
I modified mine to use an external controller. The stock incubator internal fans only run when the TEC is on, and the change in air circulation when cycling affected my DUT, so now the fan runs continuously when the chamber is in use. My controller lets me set up temperature/time profiles. The stock unit only has a setpoint, and IIRC the temperature would oscillate +/- 1 deg C around the setpoint. It can take hours to run a 50 deg C cycle, the heating/cooling rate is very slow. So you're not going to use this for thermal shock tests!
But it's cheap and good enough for what I need.