It might be possible to replicate, if you can't find what your after. Buy spotlights with covers, paint them white. Then buy some stick on BMW badges of Ebay. We have a local police workshop where they build and repair Police vehicles. I presume you have something similar, you might be able to approach them and find out where they get the originals. I would stress that you tell them you are not trying to replicate a Police bike.
Regards Martin.