I think that (years ago) I briefly considered if it would be fun to create a retro-Windows skin.
But when looking at how those old Windows panels and buttons looked, I quickly realised that I would not be able to create something that looked authentic enough.
Especially the '3D' depth effects that you can see in below screenshot that make older Windows panels so recognisable can not be replicated in MusicBee skins:
So I gave up on the idea and never gave it a shot.