Troika is the obvious choice. Expert Stylus did a full rebuild on my Linn Arkiv and it came back sounding better than new. Many on the Linn Forum swear by them for their Troikas, and they were even written up in Stereophile as doing excellent work. He usually has quite a waiting list, but there's a reason for that...
http://www.78tours.com/Expert_Stylus_Company.htm
http://www.78tours.com/Expert_Stylus_Company.htm