So the it only for the homebrewers like myself. I have only read through about half of this thread and I understand any thing more then a 20 gallon (10 gallon batch size) is no really viable, possibly because of the weight of the grains. So what is the most grain that would be able to be placed in a kettle with out breaking the pulley system or having some sort of malfunction with the hardware or the wort?
I have done 15.5 gallon BIAB, about 35 lbs of grain w/ a simple inexpensive strap
http://www.harborfreight.com/set-of-2-1-inch-x-12-ft-lashing-straps-67386.html
With a little better equipment, I don't think 200 lb grain bills would be unreasonable with the right equipment, so thats a 3B batch, say 90 gallons. This cheap rope hoist is 500 lb capacity, and much bigger stronger stuff is available FWIW
http://www.harborfreight.com/general-purpose-rope-hoist-45076.html
How big are you looking to go? I think the bag could take the weight FWIW in that the bag becomes larger with all the more material to handle the additional load.