>>3114149I'm the one who made the music box cover, and yes it's possible to make custom music box but it's very expensive
The more accessible way is to use the "make your own" music box kits where you basically puncture a paper that will play the melody you want (example
https://www.amazon.com/Kikkerland-Make-Your-Own-Music/dp/B000HAUEFY )
I did this once for my ex but for her song you'd need a wider one as the cheap music box only allow a very limited range of notes