I looked around when I needed to replace mine. Ended up w/ the replacements from napa as I couldn't find anything else.
You could probably call a company like daystar and see if they have something in the right width and diameter though.
If you do replace the bushings w/ the ones from napa, you will need a press to install. I tried getting them in w/ a hammer and it won't work, it is an extremely tight fit.