Creating identical, curved parts can be made very simple with a router sled. With the right bit this can be the quickest way to shape parts and all you need is double stick tape, wood, glue, and a router.
The first step is to transfer your curve to a piece of MDF or plywood. You will have to offset your curve by the depth of the router bit for your final pass, otherwise you will not have room to step your cuts down, or you will end up with a different curve. Each side of the sled needs to be identical! Make sure you leave plenty of extra room on these curves for the sled to move across, at least 3 inches on each side.
Next you will cut your bottom to hold everything together, this should not be done with solid wood. Make sure to leave extra room here as well for the router to have room to travel past the work piece. The last piece of the puzzle is the moving, rail portion of the sled. This can also be curved if you are doing a complex shape, but the version shown below is straight. The important part for this is minimizing flex in the rails and keeping smooth travel over the curves. The pieces you use need to be strong enough to resist your pressure downward, a torsion box style of construction will work very well here. Make sure these two pieces are perfectly parallel and fasten stops on the outside of your curves to lock everything in. These stops need to be long enough to prevent racking or twisting as you move the router sled over the bottom curves.
The last part is what holds the router in place. I simply flip the router up-side-down and place my rail system on top of it with the bit centered between the opening. Next I put double sided tape on two strips of wood and press them against router around the rails. These pieces fit snuggly on the outside of the rails, allowing the router to slide along them with out any slop in its motion.
That's it! Now wax all of the moving parts and your ready to go. Make sure you have a fence to hold your parts in the same place every time, and double stick tape your parts down very well.