When people say "Skinnable" they often mean much more than the visual skin, which is where the confusion comes from. You can Skin Theater View - but you can only Skin it in the strictest sense. You can change its appearance, but you cannot change its behavior, basic layout or navigation with a "Skin" - which is what some people would like to do.
What you probably want is "Customizable", its a rather generic word, but what people want to do is also rather generic. Some like a different look, some would prefer an entirely new interface.
With the trend of HTML taking over every interface there is, maybe that would be an idea to pursue. Extend MCWS as needed, and build a fancy responsive WebGizmo replacement, which looks good on a Phone, Tablet and PC - and incidentally, also works on every type of phone in one go, no special Android, iOS or Windows Phone magic - only audio/video playback may need some handling, but HTML5 is making advances there as well.
Serving as a template, people could build their own interfaces on top of that with all the customization they need. And Web Knowledge is widely available!
Many Android and iOS applications actually work like that, they are just a "website" masquerading as an app. Windows "Modern" (formerly Metro) apps are also based on web technologies.