There is a discussion about reproductions, here on the forum. But nothing has been produced yet.
Best bet is to keep an eye out at junkyards, ebay, etc. Yup, it is an issue.
(if the cracks are not in the way of the light, grind out the crack (v-shape), fill with plastic-friendly epoxy, sand and paint.
https://www.youtube.com/watch?v=FQpwsLpnbF0comment from this video: Just bought some to fix my Fiero GT tail light... Almost impossible to find a set in perfect condition, gonna fix a small crack. This is a Godsend!
[This message has been edited by jaskispyder (edited 07-22-2015).]