Call Prothane...they make poly bushings and I called asking them about some TeraFlex bushing replacements last year and they had what I needed and were very open to finding any bushing sizes so they could market them as replacements. Might be an opportunity for you and them.
4" Teraflex long arm lift. D30 tubed with chromoly axles, high pinion, powertrax no-slip and Warn Lockout Hubs. D35 w/ultimate 35 upgrade OX locker, 4.56 gears. NP231HD, Air on Board, Warn M8000 Winch.