Since you liked them so well I would suggest that you try to find bike shops that have really old stock still sitting around. One that isn't and wasn't into the latest high end stuff might be the best bet as those saddles were generally sold for fairly low end bikes. I am pretty sure the bikes I have seen them on were all 3 speeds.
The sort of place I have in mind is one like a little local shop near me that has fixed and sold bicycles and lawnmowers for many years. I don't think they have sold new bikes in years, but I wouldn't be a bit surprised if they had one of those saddles in stock. They apparently are still in business, but they seem to be closed whenever I go by.
I would be willing to check them out if you are interested. Do you happen to have a picture of what you want to be sure it is what I am thinking of?