@hiccup, whats the reason for putting next track and play pause buttons on each card - just for 'look' ?
I have not given the controls full thought yet, but I did try to imagine how such a Singles view could be used at e.g. parties, perhaps on a tablet with a touch screen and bluetooth speakers.
I intended that button as Cue last. (there probably is a better icon for that)
The tablet could be passed around to another person, and he could 'be allowed' to either play a song, or cue a song to the end of the Now playing list.
Play next' would not be a nice thing to do to the previous person ;-)
And, considering touch screens, the controls would probably better not be of the hover over type but always be in sight.
Other thoughts about possible controls on the cards are appreciated of course.