Your going to be hard pressed to find someone to make a mold of just the center. Then try and mount 3 parts that are flexing all over will be a pain in the but. One piece is the best bet to go with.
I don't remember if I saw it here or another site but theres a company that makes a urethane center piece but it had 3 or 4 foglight holes in the middle.
I had a similar idea to josh. Only instead of running an ss bumper over on it's own I would go to town on the metal piece with a hole saw and leave basicaly a skeleton for support/brackets then just go over it with the cover