They are getting harder to come by these days... there were several brands that had ball bearings in the steering posts but they are no longer in production. I had to settle for this one from Integy which uses teflon bushings in the rack. Not a perfect solution, but definitely better than the stock plastic parts and beggars really can't be choosers at this point:
http://www.integy.com/st_prod.html?p...w#.VFmskleLxNg



They also offer a blue one too:
http://www.integy.com/st_prod.html?p...w#.VFmtileLxNg