License plates are strictly regulated by law in each jurisdiction. However, the license plate holders, i.e. the (usually optional) frames within which the plates may be framed and mounted, are ripe for customization within reasonable limits.
Observation
Conclusion
People will enjoy customizing their license plate frames and getting those made cheaply and fast via 3D printing.
Solution
People can choose to make a statement on their license plate frame, or even 3D print shapes, mascots, etc. The 3D printing makes such personalization easy and affordable, and becomes an extra perk of choosing to buy a Buzz.
Need addressed by this product
Colors, materials, textures, text, icons, images, the countries or states you've driven through in your Buzz, the names or busts of your pets, lines from your favorite songs, etc etc ... so many variations are possible when 3D printing the license plate frames.
Further elaboration of the product
Unique frames (plateholders) appeal to many people with FOMO (fear of missing out)! VW can leverage them into #PlateSpotting, #ShareYourFrame or #VoteForMyNextPlateholderIdea, etc social media campaigns and "buzz." AI and machine vision may even turn the holders into cues, playlists, etc!
Further elaboration of the product
Since modern 3D printing allows for a variety of weather resistant materials, colors and shapes, and the price of the printing has also come down, VW might be able to offer 1-2 free custom frames to Buzz buyers, and thereafter charge for any subsequent orders of 3D frames.