I've been interested in doing this myself, it appears you need to drill two holes in your triple tree clamp so you can mount some of these.
i have also found this, but its not in production yet apparently
http://www.satoracing.com/ninja250_handleriserkit.htm
the second option would be more ideal, but it is not available.
one thing to think about when drilling holes to mount the first option, is that there is bracing under the triple tree clamp that was cast/forged when the part was created, so its not a flat surface under there. I'm currently in the process of deciding what i want to do with that situation.