Cost depends on what you adapt to make it work. As far as I know there are/were no kits but I could be wrong.
You might do some research on the Police model control assemblies. They used running boards mounted a little more to the front.
Also if you do make forward controls the ends of the engine are going to be in the way. The pegs are either going to be really wide to let your legs go around or high so you can go up and over the stator and pickup assemblies.
