I've never messed with that series of trucks (not that I wouldn't want to, just never had the cash when one would pop up for sale) but I've gotten cab mount bushings for newer dodge trucks from pro thane. There's 1 other company that makes such bushings too, name escapes me.
Go somewhere that has a decent size magazine rack and pick up one of many truck and/or jeep/4wd magazines, they advertise seemingly everywhere.
Thanks for the reply volaredon. I guess im going to have to call some one and speak to someone directly because i cant find them listed online anywhere.