I picked up the latest copy of Truckin' and near the back I saw an ad for a company called Sulastic Suspensions (
www.sulastic.com). What they sell is a replacement shackle for leaf-sprung rear ends that is supposed to offer an improved quality of ride as well as a better-handling vehicle.
The reason I checked them out is because my '96 SWB GMC rides like crap. It's got some harshness whenever you encounter a variation in the surface of the pavement. It seems like my truck wants to bottom-out, and I'm really getting tired of listening to my wife complain about it. I don't like it either, but compared to my '69, there really isn't any comparison, other than daylight and night.
I've changed from Toxic Shocks to Monroe-Matics and now Monroe Sensa-Trac. I've thought about removing a leaf to get a softer ride, but I'm not convinced that it is the right thing to do. On smooth surfaces, the ride is good. I don't do any hauling, so that isn't an issue.
For you old-timers, the best comparison I can make when I look at the Sulastic components is to a Houdaille friction shock....and I know that ain't what it is.