I've just finish the skin this evening, back from work. Here it is: [grab the link in the first post!]
Actually, yes, with the bitmap skinning tool it's possible to do a lot of things, i manage to do something approaching a lot my photoshop file. But i didn't change the layout though.
The volume bar can't look like in my screenshot, because there is no setting for a filler image. And in the final skin, there is a little yellow block remaining at the beginning of the seek bar even when nothing is played (but it look cool : ).
And last thing, the buttons hover effect doesn't render really well sometimes (for a few milliseconds, it seems like the button become a grey block). Maybe if the buttons effects was all in the same image, the transition would be smooth ? (0px to 20px: you'll have the default button, 20px to 40px the hover button etc ... ) Anyway, most of the time, the transition is ok.