Design and build a camera management API

Our games won't be very immersive if our view is stationary. We need to design and build a camera management system which allows use to spawn as many cameras as we want, have each one follow a path defined by waypoints and/or a target entity. Each camera should maintain a current frustum, it's own projection settings and associated viewport settings. The system should allow for multiple viewports with associated cameras (e.g. a rear-view mirror in a car etc.)