I've researched that and it appears that since V riser is sitting on 4 bolts with unusual angle there're no alternatives to the OEM riser. Nothing at all. Nobody makes them for V specifically, because any shorter riser would cause problems with clearing the tank and fairings.
So, I've installed Rizoma risers, but had to drill the top-yoke (soft aluminium, so no drama, except for wife's major bewilderment with noise and mess). If you decide to do that, some words of caution: most 3rd party risers are for fat-bars, so you'd either have to use spacers, or change bars; and be very carefull when choosing the spot to drill - you need to make sure there's a space for a nut underneath AND the bars clear the tank AND the key has space to go into the ignition switch (I buggered this one and had to kut off the rubber from my key).
But then, it's all good fun! ;-)