I didn't document the build step by step but I think the final results are worth sharing.
I based the build on various plans and ideas found everywhere on the net and added a little of them all into my own adaptation.
I started with the dimensions required to contain the 6.5 gallon Mini-Brew I received for Christmas. This ended up being 14" x 18" x 42" inside dimensions.
Next I aquired a $10 mini fridge and gutted it's AC components.
I then cut 4 sheets of 26ga galvanized metal 18" x 46" and 4 sheets 22" x 46" and turned 2" inches on all the sides to form 8 - 2" deep pans. These were to be the 3 sides and door. I made the top and bottom the same way.
4 of the pans were formed slightly smaller than the other 4 so that 2" styrofoam insulation could be placed in one and covered by another forming an insulated panel. The top and bottom, again, were done the same way.
I assembled them overlapping and held them together with 3" decking screws from the outside. All the overlaps and seams were caulked.
Prior to fitting the top, I cut the mini fridge components into the back panel and finished it off with a couple of tool box type closures on the door and a temp controller that I had made previously.
So far it's working flawlessly.
I am a metal worker by trade and got the metal for free, the fridge for $10 bucks and my previously built $30 dollar temp controller. All the hardware I had stored from who knows how many years (pop rivets, hinges, closures etc).
So all in all it cost me about $40 bucks to build.
Here are a few pics: