By the time yorue done forking cash out for whatever way you decide to go with this. It will have been cheaper to buy a Vapochill
When i added up all the money i spent on watercooling hardware, case mods, and things like that. I was within $30 of the price of a vapochill which would be magnitudes better cooling. So my vapochill is on its way to me as we speak. Going to drop watercooling ans go with phase change.
A comment about the mini-fridge idea. I think that putting a res inside one would overburden the fridge. Also something else to keep in mind. when thinking about yoru flow rate, how much time is any given amount of water going to be inside the fridge? even in a really cold setting it would take at least a few minutes for it to have any effect on the temp of the water. Just food for thought.