I have an OEM cup holder just sitting around (I no longer have my Z) that has custom illumination. It was my first prototype so to speak. The EL wire used is considered orange but actually lights up more yellow and doesn't quite match the car's illumination. After this first attempt, I ordered a new cup holder and used a red wire instead which much closer matches the Z's interior illumination.
You can simply drop this in or swap out the EL wire with a different color if you wish. You'll need an EL wire 12V converter to make this work. I also make no claim to a warranty of my work of the EL wire.
A new OEM cup holder is around $90; which is flat out ridiculous if you ask me.
Buy this cup holder for $30 + shipping.
Pics can be found below in this post.
Looking to do illuminated cupholder