Mine appeared to be that bad too. They didn't look like they would make the few miles needed to get home. They may really not be as bad as you think. Take one off and start grinding it clean. These springs are beefy and I would be suprised if they weren't salvageable. Mine totally were despite their horrendous looking state. With a lot of elbow grease, I was able to knock off and grind down to perfect metal. They looked like new. I also had to replace several clip bolts which were rusted completely through. In fact, I replaced all of the bolts with new grade 8's.
I tried repeatedly to find replacements, to no avail. They are a very odd size/configuration which no local spring shops had. I was told a custom set or conversion to a more common trailer spring set up was my only option. Very pricey. That was the reason I started trying to clean mine up. Glad I did! Now if yours are totally shot from overloading, that might be the deal breaker.