The Game Boy Color is the first Game Boy from Nintendo who released under different colors. It allows gamers to choose which color suits their personality. Nowadays, there are also a lot of Game Boy Color shell available on eBay. You can get several shells and combine it to make it a unique Game Boy Color. The following video shows how you can do it.
You can extend your customization with installation of front light kit for the Game Boy Color
Here is a better way to install front light kit with LOCA