Dirk,
Again, sorry to hijack the the thread. I would think someone has something laying around. I have Challenger versions but not Cuda. That said, I have redone my own seats a number of times and they are not very complicated. Given you started with bare frames, perhaps a different "ask" might be fo measurements or a drawing with measurements; anyone with a 70 Cuda or Barracuda (not a grand coupe) could get these pretty quickly I would think and if your upholstery guy is good, he should be able to replicate this pretty easily especially if you give him pictures of what the seats look like when done. Another option might be to buy some of the cheap covers that are on Ebay to use as patterns (I would go option A first).
Sorry I couldn't be of more help.