In order to take out the action bar shadow you must use js, here is the code to do it.

    if (page.ios) {
        navigationBar.shadowImage = new UIImage();
        navigationBar.setBackgroundImageForBarMetrics(new UIImage(), UIBarMetrics.UIBarMetricsDefault)
    }   

I think it would make sense to make use of the border css property to over ride that. Setting border: 0; on an ActionBar, should remove that naturally.

The other thing is I cant seem to set the actionbar to transparent/transulcent? background-color:transparent; or background-color: rgba(0,0,0,.8) would make sense, in combination with the removal of the shadow on the action bar, it would give me a clean, transparent/transulcent actionbar.