I always wonder about these projects, wouldn't it have been easier to simply resto-mod an actual '69 body with all the modern fixin's? Engine, suspension, interior, and accessories can all be brought to modern standards quite easily. You can even buy a brand new '69 fastback body if a solid original couldn't be sourced. Some of the safety stuff would probably be difficult (airbags and the like), but I'd wager the guy building something like this isn't terribly interested in side airbags, etc.
I get the idea of these projects, but no matter how well done (and IMO, this one is well done) they always look a bit "off". If you want a car that looks like a '69 Mustang, start with a '69! Just my opinion...
That said, whomever did build this car did a nice job.