Anyone built one? If so, how is it working for you? Tips? Building description ?
I don't see the benefit unless you plan on using it to store food short term till it's time to can them.
Long term food storage is where it's at, investing in that would be better. I built a summer kitchen, we do all the cooking when it's warm out there. I use it to produce maple syrup, make homemade wine, can foods and make apple cider. Lot of cleaning up with the big sink, an old 1950's gas stove sits next to the sink, a pull out sprayer reaches the stove top for filling pots. A refrigerator as a cellar of sorts keeps things short term, I brine venison for meals and pork belly for bacon in it. The bacon brine takes 10 days then 2 to dry after washing before smoking.
The summer kitchen is probably the most enjoyable addition to any home. My wife's friends all want to prepare food here.
Right now there is 5 gallons of finished white wine, 5 finished red and 5 blackberry currently fermenting on the counter, 5# of pork belly brining in the fridge with 3 gallons of finished hard cider. I hunt with others in S. Ohio on a friends old homestead. Going to surprise everyone with the bacon.
The summer kitchen turned out better than anything I could've imagined. It's attached to the house, a back porch that I enclosed and didn't make part of the interior of the house. I'm a builder, it's not just a room with stuff in it, very attractive, nice windows, trims with crowns, 4 doors one out back to the green house. The garage is on the opposite end of the porch/kitchen, it has been my shop since we built the home back in the late 80's. The wood fired boiler that also heats the domestic hot water is out there. Heats the home, the summer kitchen and the shop, It's not a traditional wood stove, it doesn't burn up, it's forced to burn down through ceramic champers and completely shuts down when the water is to temp. It burns at 2000 in the boiler, by the time it reaches the chimney it's 300, very efficient.
To go from the house to the summer kitchen to the shop I never have to go outside. As long as I have fire wood in the shop, I don't care what it's like outside, and the wine helps
Long story short, I'd do the summer kitchen.