An easy way to make a lower third directly in FCP is to find some b roll, use a gausian blur to distort the image to your liking then crop it to the desired size then do the same with a solid color, cropping the solid color to a thin line then place one line on top of the lower third and a copy of that line on the bottom to create a border. I do it all the time and it takes 5 minutes and looks great.