There's a tub for sale now in the classified section.

There's a forums member, Navyeod, that has a tub for sale, it's out of a '58 Overlander.

I refinished the tub in ours. It had small hair line cracks & it came out looking & working just fine. You may want to ask some of the vendors/renovators here on the forums. It seems like I saw one for sale not to long ago, if I remember where, I'll let you know.

Check "SilverDollar" 's thread yesterday "parts for someone?". It's a link to a scrap late 50's Airstream on Craig's list.

Good luck

Did you have to replace the tub in yours? I can't seem to find one.