A friend in my local AACA was waxing enthusiastic about a company that makes brand new gas tanks for his '41 Buick, and he gave me the company name: Tanks, Inc., out of Monticello, Iowa. http://www.tanksinc.com/index.cfm
They do NOT make Hudson tanks, but I wonder if anyone who needs to replace his tank, might be interested in contacting them to discuss the feasibility of making a limited run of Hudson tanks (probably for Step-Downs, since if any Hudson model would provide the numbers necessary for economies of scale, it would be '48 through '54. (I'm hoping they all have the same size tank!) Another thought: maybe a tank currently made by the company, for another make of car, could be easily adapted.
At any rate, it is at least possible that a new steel (not stainless) tank could be produced that wouldn't cost much more than the price of rebuilding an old tank. Anyway, it might be nice if someone looked into this, on behalf of his fellow owners. (I own a '37. No hope for me!)