I haven't heard of one. Is there something happening with your bike that makes you think you need one? The front end geometry of a Sportster is set up for great straight line stability, have you made any other mods?
Here ya go, not cheap..... http://www.storzperf.com/np_Sportsterdamp.html
My thoughts are unless youv'e jacked the rear with some tall shocks making the steering quicker and ya run fastoften its overkill.
the 04 and up has a different mount,daytona steering stabilizers are reasonably priced, trak-tek used to sell the later model and shindy performance does also, custom chrome catalogamong others list the 03 an down model
I'm looking for one too. You do need when mods are made. If you feel like your going to lose it on the freeway. YOU DO NEED ONE. I racked out and got longer forks along with a new tri-tree and 18" ape hangers.
I need one too.