Here is the proposed design:
Get a 10 gallon Rubber-made cooler. Replace the spigot with a standard Igloo Cooler drain (the threaded style are 3/4" garden hose fittings). Cut a hole in the lid for the neck of the carboy to stick up through. Since it is going to be cut anyway, fill the lid with great stuff foam insulation. Near the top of the cooler, cut a hole through the wall and install a 3/4" plastic through hull fitting for a boat (got several hanging around), and seal it up with 3M 5200.
For the cooling side, I am going to use a 50Qt Icey Tek that I already have. It already has 2 drains, which are 3/4 pipe thread. Off one side, a short length of hose will come off the cooler and into a bait tank pump. From the pump it will go to the fitting at the bottom of the Rubber-made. The through hull near the top will be the overflow, and connected to the drain on the other side of the cooler.
For heating, an inexpensive aquarium heater will be put into the Rubber-Made Cooler.
All of this will be controlled by a Ebay aquarium controller......which should arrive any day.