Alternate fuel tank?

[Pat80FLH]

So I'd really like to get this thing out f my garage. It's a 1976 GS750 that was brought to me on its' side, with the carbs disassembled and the parts tossed in a box. Then pushed outside for multiple years. I' ve got it running, stopping, charging, new tires chains brakes. Did the work as a favor because I felt sorry for the lady. I had ridden it all over, gotten it inspected but when she came to get ot it was puking gas out the overflows. Rust washing out of tanks and fouling needle seat. I attempted a derust but the metal was so thin that the hardware I dropped into it punched through the sides. Tank now has a dime sized hole and as far as I,m concerned, it's junk.
Which brings me to my problem, where can I source one? Beat up used are crazy priced. I'm looking at new aftermarket ebay tanks but can't seem to match the specs. Anybody know of anything that works without a ton of fabrication?