I know that this may sound totally contradictory, but one of my bikes has the reg number 110 OXX.
I paid £500 for it about 7 years ago - on top of the bike that it was already on.
At the time I wasn't quite sure whether to go with it or not, but went with it anyway.
I'm not bothered about it all, only one biker has ever said thats a cool number plate (must have been into plates). Anyone else that asks I just say it came with the bike. So friggin what, haven't had it valued, the next pillion bike will be another blackbird anyway, just not bothered.