Shouldn't the "now playing"-view and controls be on top? It's the only item in there that is dynamic and it feels weird that it pops up in the middle of the speaker volume and microphone volume controls. If music is currently playing you are also most likely to access these controls if you are opening the indicator menu so it makes sense to have it on top instead of on the bottom of the list.
I love the concepts, really. I like so much the way elementary is getting. However, there's something I don't get. I heard DanRabbit saying that sound applications like Beatbox were not going to have an independent volume control, due to the minimalysm and cleanliness that elementaryOS always tries to improve.
I mean, is that still planned? 'cause in this mockup there's a system sound icon, and that has confused me.
Thanks for everything believe me when I say I really like your mockups