There's people that take the OEM valve covers and use a laser to cut half circles out of the part of the valve cover that covers the cam gears. They're called moon cut valve covers or something like that. Search ebay to start, I know I've seen them there... I've also seen them on tuner sites too.

For the plastic cover that covers the side, just use a roto-zip or something, they come with a device that's like a compass and allows you to make perfect circles.