you could always get a frame here and put all the gear from the o.s one couldnt you?
pretty sure that it is near impossible to register one (bike) from O.S. with lots of $$ anything is possible though.
i once had an xr 650 for a couple of years. had it tarded also. they are a good solid bike, but are lacking in areas. you could spend loads of money on one and make it trick though. i would like to see a xr motor in a crf frame.. that would be cool!