here is the best on imo. i run it on some of my revos it works very well or you can make you own linkage. but this the only one that i know of. here is the link to the item. you can go wrong with it.
http://www.impaktrc.com/product_info...roducts_id=926
what motor are you running with it? it work with nearly all the bb kits as well. i have not used it with the Qoncepts kit yet but i think that i am going to try when i get my jammin 28. hope that helps.