This is how I used to do it
I got a free large chest freezer that was on its way to the scrap yard
I bought this controller from my brew supply househttp://morebeer.com/products/johnson-digital-temperature-controller-wired.html
This controller is fully programable for heating or cooling.
I set mine to come on at 95 deg and shut off at 100
I then got a small heater like the one here. http://www.ebay.com/sch/i.html?_nkw=lasko+ceramic+heater
You have to take it apart and disconnect the internal thermostat so it will run continually
This is very easy. Four screws and the heater with come apart in two half's. Cut the 2 wire that go to the temp dial on the top and wire then together.
Now simply plug the heater into the controller and the controller into the wall.
The heater will hold the freezer temp at what ever you want.
I stored a doz 5 gallon pails in the setup for several winters in Michigan and never had a problem
Once the honey in the buckets comes up to temp the heater seldom runs. One winter I had work to do all day up there and the heat only ran for 45 seconds, once a hour