I have run into crawl space gas water heaters all the time in the past. Still was able to find a replacment. As of recentl I have not, so I am not sure if what your saying is true. If a low boy heater is not made any more and I didnt want to have the home owner hire an electrion, I would consder a tankless heater. Or even a small boiler with a sideways installed storage tank. I do help this helps.