Actually you can build a 67 Camaro or 67 Mustang right now, there is a company that sells assembled shells, made from reproduction parts. But the price for that shell is about what you're quoting about $15,000-17,000. But that's just a shell. No Suspension, no drivetrain, no windows, interior, no nothing but body shell.
If you took that body shell, and did all the work yourself, all the additional parts, unless you found a lot of used, unrestored parts, would at least triple the price, i've heard of nobody who's done it for less than $50,000.
If you're interested, look up Dynacore, it's one of the corporations doing this. Several other bodies than just 67 Camaro and Mustang too.