Not sure about current pricing. My price was the first-tank development price which included all the trial and error, fitting issues, messing around to test things, changes at the last minute, etc....so it was stupid expensive. I bellied up simply because Ii really wanted the extended range, the process was interesting and challenging and at the time I could afford it. Once he got the pattern down and used a cad cam process to cut out the pieces the price fell significantly. You would have to ask him where he ended up. I believe every tank he built became less expensive.
Shane never did have "production" set up so there was no production to stop. The tanks were made one at a time and done to order.
I certainly understand why someone would simply want to carry cans. Unless you use your vehicle in a way that requires extended range, adding the larger tank would make no sense at all.