got tired of opening the garage fridge to pour a draft so went out and bought a small chest freezer to convert. I found some instructions online to modify the thermostat so it would reach beer friendly temps instead of using external temp controller. Well long story short, I fubar'd it, due to some impatience and slight temper since it wasnt working. So now the plan is to wire nut the leads together, eliminating a thermostat altogether and using the temp controller anyway. Question is, (not knowing much about appliance wiring...) this should work without the original thermostat, right?

I am not sure does it turn on if you just plug it in? The temp controller just controls when to turn it off and on but you need to set the thermostat at its lowest setting otherwise the fridge thermostat will over ride the external one one. The external one just controls the power to get your temp.

At least that is the case with the Johnson controller I am not sure if any of the others are different but I doubt it

I believe Stinkfist is right. If you plug in the freezer and it gets below beer temp, you should be fine. The external controller will cut power to the whole unit when it reaches the set temp.

Be sure to keep us updated.

You shouldn't be tinkering with electricity unless you know what you are doing <----disclaimer. If you are going to tinker I assume you know what you doing.
On my freezer there were wires for the power. They split and powered the fan and the thermostat. You should be able to bypass the thermostat and have the freezer always on. Then your external thermostat would regulate the temperature through power cycling.
My freezer is ancient and the wiring was pretty obvious. It may take some searching with a multi meter to find the right wires. Im also not 100% sure this will work on newer appliances. I would call an appliance repair shop and tell them your plans and get some expert advice.