I'm currently using one from Rizoma on my gen1. It us integrated into the grip. Pretty universal setup. I'm sure it would probably work for gen2 as well. Comes with 3 or 4 different cam profiles in the box.
I epoxied some schedule 40 pvc pipe to my previous gen 2. Pretty much anything to enlarge the cam gets the job done & will likely be quite a bit cheaper & just as effective.
EDIT: This pic isn't a vmax sleeve but this is exactly how I did mine. Used a dremel tool to smooth it out. Before putting everything back together with cables in place, put the sleeve into the throttle assembly & be absolutely sure it spins with NO binding...I do recall having too much material the first go around & had to grind down the pvc a bit.