I used one type of fuel tank for Betsy
Portible Marine Fuel Tanks
These are tanks designed for use on small motor boats.
The tank is made out of polyethlyne. I did a lot of whinging over fuel tanks before selecting these. For various reasons I wanted a stanless steel tank but non were really to be found. I believe that boaters have had many of the same problems. Eventually they all seem to have settled in polyethlyne as the proper materal for fuel tanks.
Oddly enough plastics have some great advantages when used in systems that have to deal with corrosive materials and enviornments. For instance CPVC appears by the literature to be almost inpervious to most solvents and chemicals. For instance it deals fine with copper chloride which will eat stainless, brass, iron, steel, etc etc.
These tanks have a couple of problems when used for Betsy. The main one is that they are small and they have a dip tube for withdrawing fuel. The tube is 1/4" which makes it hard to pump a lot fuel out of the tank. They also don't store well. I had much trouble with priming the pumps when using these tanks.
Polyethlyn Water Tanks
These may be the solution. They are square, and have large drain ports on the bottom of the tank. You can get them in sizes up to 100 gallons.
Standard Steel Tanks
These might be okay if colorants are added to the fuel after the pump. In that case the material just has to deal with Alcohol and or Methonol. Biggest problem then becomes water like any other fuel tank. An advantage of this is that one may be able to use real metal fuel tanks with flashback arrestors and what not.