Art Morrison makes a kit for a 9". The full kit is spendy, but you can buy individual components. It would probably work with an 8 3/4, but if you have a cast center section rear, you'd have to come up with a way to attach the 3rd link atop the housing.

Take a look at the design Factory Five uses on their Cobra kits. It's made for an 8.8" Ford, the 3rd link comes off a bracket right next to the centersection. Ideally, the top link would be at dead center, but offset a bit will still work. It would be really easy to piece together a set up like that for just about any application, and under a truck, you could easily fit longer link bars. Throw in a panhard bar and you're good to go.