The 50 Chevy coupe shouldn't be all that difficult to come by, quite a few still around in original condition or mildly customed.

Several years ago, there was a company named Deco Rides, Inc. that was making both hardtop and convertible 39 Zephyrs. I thought they had sold out, but I see that the founder Terry Cook is still in the business. The show car "Scrape" was one and was in nearly every car magazine back in the late 90's. http://decorides.com/scrapezephyr.htm

As for the Delahaye, the same man who founded Deco Rides, is now working on a number of upgrades to old cars of which one is the Delahaye. They say they can build one for you for about $600k. Don't think I am interested, but others may be. http://www.delahayeusa.com/