I felt compelled to bump this with my own. Let's see who has the most beautiful looking OpenMPT out there!
I'm not saying this is "beautiful" but certainly the most easy (despite a couple of elements not playing nice there with stubborn black text) on my particular pair of eyeballs:-
BTW, I completely agree that this software should not be skinnable unless of course it will in no way interfere with the performance and compatibility of the software, which is the great thing about it. Nothing worse than audio software that tries to look like a game UI and then struggles to mix even 16 channels together at once. OpenMPT FTW!