The mockup is very promising. I wonder if in the next revision you could check into consideration an option to locate the Player Controls Panel at the top as it's impossible with the current skins.
Have look at the topic
- the feature request is quite popular.
As a solution, I'd suggest to move all player control buttons
form the bottom bar (which IMHO seems a little bit too wide in your last mockup) and locate them at the top main menu bar ( between the search field and Minimize/Maximize/Close button
Saving the space makes GUI less cluttered and allows to work comfortably with the application on low resolution or small displays.
This approach is becoming more and more popular with Internet browsers design.