This was my thought this weekend. I have cancelled my custom made full length rear mudguard as I don't want to cover up the rear tyre, I think the fat rear tyre is something to show off and not hide. Guttermans picture are very helpful, but I do wonder how a "full size" legal UK number plate would look hanging from the side. I have been pulled over for an undersize plate in the past, so don't want to risk it again. The other option may be a tidier take on the rear cluster with integrated lights, some like this: