There's a lot of positives to these repro bodies, and if the quality's there, I don't see any negatives. Yes, they are expensive, but have you guys priced reproduction street rod bodies lately? A fiberglass '34 Ford coupe body is over $10,000 for fenders and all, and a steel '32 coupe body only is over $20,000. Not only that, but street rod prices have been a little "soft" lately compared to high-end '60's muscle cars, so you could easily spend more to build a street rod that's worth less than a nice '67 fastback.
As far as having a "real" Mustang as opposed to a repro car, that's pretty low on my list. I don't see it as any different than my Shelby clone. I started with a nice, clean original '68 fastback, but wanted a '67 Shelby. I chose to build what I wanted. Is it a "real " Shelby? No, and I will never claim it is a genuine Shelby. Building cars isn't about what you start with, it's building what you lust after. If I were looking for a nice fastback today, I would have to consider the Dynacorn '67 very carefully. How can you not at least add up the total cost of a finished NEW car with fastback prices so high these days? If you want a coupe, great. Prices are much more affordable, they are great looking cars and you can do whatever you want without everyone whining about you cutting up a rare car. But if you want a fastback, they are getting pretty picked over, and the ones that are left are both expensive and/or badly in need of expensive bodywork.
A couple of years ago, a local car builder looked high and low for a '67-'68 fastback for a customer. He even flew to Las Vegas, only to find the car he was after had sold a few hours before he got there. He ended up buying a decent, high-mileage '68 fastback for $13,000 locally. Since the car was going to be a complete custom, about the only thing he used was the body shell, and some of it had rust issues. I'd bet money he would've gladly slapped down a few more dollars to get a fresh body that needed no work.
The bottom line is that Ford isn't making '67 fastabcks anymore, so prices for originals probably isn't going anywhere but up, which means at some point, those $16,000 bare bodies are going to seem like a bargain in the near future.