Yes, buell fanatics has the best so far (they claim).
Also, look at the V-blast exhaust system with the remapped ecm, they sell along for X-tra catshingas ofcourse;
Otherwise Twin motorcycles (Martin & Dris) is releasing one now. They are all pretty expensive. But hey, if you buy one, tell us about it. I think the original -04 clutch ramp works splendid, even though i used to have Müller power clutch before. Yes, before i bought xtra clutch plate kit which is not compatible with Müller.
The Magura i would not buy. It's not without a reason Twin MC is releasing one.