There is a property android:maxHeight which does exactly what you need. You should set the android:thumb drawable bigger than the maxHeight to achieve the slick seekbar effect.
For example:
<SeekBar
android:id="@+id/whiteBalanceSeek"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="3dp"
android:max="200"
android:maxHeight="3dp"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:progress="100"
android:progressDrawable="@drawable/slider_progress"
android:thumb="@drawable/thumb_img" />
The slider_progress drawable was taken from here and the thumb_img is a bare PNG with a red circle.
Here is what I got:
