I have installed a 6" riser on my 2004 Vertical Edge 800. With that much rise it is necessary to lengthen wires, throttle cable and brake-line. You should have enough length to do a 3" riser with just re-routing your wires.
If you go to the 6" riser (which, for stand-up ridability I recommend) get yourself a PowerMadd (or Goldfinger) left hand throttle and that will extend your cable enough for the 6" riser. Next, take your existing brake hose into a decent hose shop and get them to build you a longer hose. This should save you about $50.00 from buying one of the "aftermarket' guys. Next, take notice of your wiring harness in the handlebars and you should see that most of the leads have a 2 or 3 prong plug-in and you can get cheater cords to fit from Canadian Tire. You should only have to extend 3-4 wires yourself.
you can go up to 4" with out having to extend anything. the tallest i have got with only having to extend break and throttle cables was 8" anymore and you would have to extend wires.