I ended up moving to a 50 watt submersible aquarium heater. I went with the Aqueon (pic below) one – primarily because it had a built-in temperature control. This will allow me to either max the heat out or adjust it if I needed to.
I tested it in a 1 gallon container as well as my 5 gallon carboy. The heater worked well and will heat the water in both congtainers, to about the same temperature +/- 1 degree. If you consider the difference in volume of water, the greater you go, the more heat distribution you should have, so a larger container should provide more efficiency and a steadier temp – I just didn’t have the room to keep a 5 gallon carboy in there, when it could be filled with wort.
I monitored my temps a couple times each day, just to make sure I wasn’t messing anythingup. I did find out that with the 1 gallon container, I had to crank the temp up on the heater to about 80 in order for it to balance out in the freezer and allow my fermometer to stay around 68 +/-.
All-in-all, I think this is going to be very successful during the winter months. I will be looking into a 3 gallon or so container, one that fits on my freezers shelf, in hopes to fine tune my adjustments and distribute the heat more evenly.