Do you know of any source for a full size one that could run on natural gas? Like you said, looks like they are all quite a bit smaller (or huge industrial systems). I do dislike the noise of refrigerators and if my current one fails I would like to try a gas powered replacement. Also, natural gas in California is way cheaper per unit of energy than electricity (thanks to Enron and other factors). A gas frig could be cheaper to run than electric here.
I got one from Dometic. I don't think they run on natural gas though, just propane.
https://www.dometic.com/en-us/us/products/food-and-beverage/...
Personally I use an ammonia absorption fridge, the kind of thing you usually only see in hotel minis and camping vans, because of the noise.