I personally think it's a goofy idea for a "kit".  If you want a fastback that bad, just go get a new Dyacorn body and you'll have a better base car than even Ford supplied.  IMHO better than some hacked up deal that destroys one car, possibly two.  And not necessarily more expensive if you have to pay for the work.  

I agree. Why hack an existing car because its not what you wanted to buy?

Like you, I say buy the Dynacorn and build what you want. Even ifyou have to do some work on the Dynacorn body for fitment, etc. I think you're better off in the long run. Brand new metal always beats patches in my book.