Making your own hardware to expand a game's functionality is a fine skill that deserves plenty of recognition. But doing so while taking the luxury to add artistic elements to your work is a thing only left to the gifted ones.
This is what UKVAC forum member "ajhippel" has done with a Crazy Climber highscore save mod kit, made it memorable by adding demo-scene like music and effects to his work.
More info over here:
http://www.ukvac.com/forum/topic351563_post950717.html#950717
Sample music routine:
https://gist.github.com/ArcadeHacker/44cdf7dc03638c2f271ca8b5b6a77fef
Preservation and Reverse Engineering of Arcade Video Games