Hi I did some research into this a while ago, it's not cheap..
A set of wheels from Yamaha was quoted at �740 inc vat but not including bearing discs etc Bearings �20ea, Discs Front �140 & rear �90 i'd probably just swap the sprocket over to save cost.

The other (cheaper?) option is to get a set built I approched Talon who pointed me toward Central Wheel components. I talked to them at the uk Dirtbike show and they said they could build a set for about �500 if I supplied the hubs which are rear �135 + vat & front �128 + vat from yamaha. A cush drive is about �25 + bearings & discs etc.

Hope this helps!
Gory

__________________
What do I know about motorbikes? I fix London busses for a living....

:tenere: Mods so far.. Barkbusters, ARDcases on Holan racks, Garmin 550t & Ram adapter, Lowered metal mule links & forks dropped by 15mm, DNA filter, Pivot Pegs, Symtec heated grips, Yamaha engine bars, Breather box, Touratech rear rack & tail pack (large), Polisort freeflow mud guard (when i'm trail riding), ciggy adapter, waterproof rectifier wiring, more to come...