I know what your talking about. I have the same tail light issue as you. I just went to a local metal shop today to see if they could make some new one's out of aluminum and they said it could end up being around $300.00 each. There is a local body shop that is known for custom work that could make a copy of my plastic tail light assembly out of fiberglass. If you need some templates I could have this done for you. So it looks like i'm going to have to repair mine with fiberglass and live with it.
Thanks for the offer of the templates, but not necessary. I was hoping for some solution without reinventing the wheel. I've considered making a mold and building a new set out of fiberglass. But for right now I'm happy to have the lights working and will be working on more pressing needs.