How big do you want the seek bar to be?
The TNT skin I have done here
http://www.bsplayer.org/index.php?p=...38f7b5b0310b70
has a decent seek bar.
You could make a skin just the way you want it. Then the seek bar could be as big as you want.
Give me an idea 20 pixels high by 800 wide, or 50 H x 400 W etc.