Nice! I think it's better than ChosenOS's 100% black line (this one doesn't look good with shadow and eye candies in OS X)

I think it's perfect except the toolbar button which seem odd in some way. Maybe flip it vertically and then cut the right window corner diagonally to match the toolbar button (parallel)? If you like to keep the corner then just ignore my suggestion

I'd love to try it out when it's ready