i changed mine from 10/10 to 14/12 and because the profile on the rear is larger than the front, it is almost the same as having 14/14 but you dont neccerialy have to change the sprocket of swingarm unless the swingarm is too small.
wouldnt have to go that extreame, depending on whet your running originally if your going from a jump from 10/10 then there will be major modifications
i think everyone should be riding 10/10 i dont see why not... thats what crf50s are all about 10's what happended to the little things =(