A friend and I have just completed this. A 20 cu ft chest freezer was used, a insulated box was was made over the compressor hump side for the fermenter side. Its large enough for 2 ale pales to ferment lagers in. The other side can fit either 6 or 7 kegs, I forget. There is a small space heater in the lager side that runs about 7 minutes per hour (it takes a while to actually start blowing hot air). The keezer side runs 3 minutes every hour. We will be making a build thread soon, i'll repost the link here when we get around to that.