Nanner Split said:

Update:

Asked a designer buddy of mine for some tweaks, and apart from the "selected button" and "activated button" highlights (which aren't on there because I haven't gotten to them yet) I'd say this is a pretty solid final design. What do you guys think?

(Full size)

The basic design is fine. I would make the translucent gray bar behind the track selection shorter (bring it in a few pixels, top and bottom), so that the thin empty line below it is taller, if that makes sense. Right now it reads as a 1-pixel line, and it looks uncomfortable.