OME made some for the rear of the a-arms only, but not the front. I think i still have a spare set of rear OME poly bushes. They take a bit more wear than the fronts do i believe, and the rubber ones work fine in the front.
Calmini makes poly bushes, but i don't think they sell them separately.
OME also made replacements for the rear trail arms (both front and rear positions), but they discontinued them a year or 2 ago, but i've got a spare set of those as well.